@proceedings { 296, title = {Impressions from applying ISO31000 to avalanche mitigation projects}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {ISO 31000 is an international standard for risk management. It offers standard risk concepts, terminology and processes for diverse organizations and their component departments. Few applications to avalanche mitigation projects are publicly available. While not authorities on ISO 31000, we share our impressions from applying it to examples of avalanche mitigation for infrastructure. ISO 31000 defines risk as the effect of uncertainty on (organizational) objectives. These effects can be positive or negative. For organizations ultimately responsible for managing avalanche risk (the risk owner), their objectives often include profit, positive relations with the workforce and environmental stewardship. These objectives are subject to diverse influences including uncertain negative events such as loss of life, employee injuries, property damage or transportation delays, all of which can be caused by snow avalanches. To illustrate ISO 31000 concepts and terminology, we use a simple example of a proposed mining road threatened by snow avalanches. Avalanches can threaten worker safety and cause delays of ore as well as of crew changes. The mining company (MC) contracts an avalanche consultant to assess the avalanche hazards and recommend mitigation options. The consultant recommends a mitigation option involving a deflection dike combined with an avalanche forecasting and control program. MC rejects the recommended mitigation option because the proposed dike would affect a stream, i.e. affect MC’s environmental objectives, which were not part of the terms of reference of the contract. To ensure ISO 31000 is implemented in the contract, MC issues a second avalanche mitigation contract that includes assessing the environmental risk. Following completion of the second contract, MC selects risk treatments including a forecasting and control program without static defences, a worker safety program specific to the avalanche prone road, increased insurance for the cost of potential delays in shipping ore, and expanded liability coverage. ISO 31000 offers a framework for an enterprise-wide management of risk i.e. the effects of uncertainty on the organization’s objectives. We illustrate how ISO 31000 can be applied to an organization responsible for managing avalanche risk and the benefit of it being applied at all levels. }, keywords = {ISO 31000, enterprise risk management, uncertainty, organizational objectives}, author = {Jamieson, B. and Jones, A.S.T.} } @proceedings { 300, title = {Limitations of an infrared camera to measure snow pit -wall temperatures}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {Kinetic snow metamorphism is known to be crucial for avalanche formation and is driven by temperature gradients. Faceting close to a crust can be observed even in the absence of gradients needed for kinetic metamorphism when measured with thermometers 10 cm apart. Interesting results were found with recent studies that visualized small scale thermal structures with an infrared(IR) camera. The studies found melt-freeze crusts as being warmer or cooler than the surrounding snow depending on the large scale gradient direction. However, an important assumption within the studies was that a thermal photo of a freshly exposed snow pit is similar enough to the snow internal thermal structure. In this study, we tested this assumption by recording thermal videos during the exposure of the snow pit wall. The results show increasing gradients with time in the first minute both at melt-freeze crusts and at artificial surface structures such as shovel scours. Cutting through a crust with a cutting blade or a shovel produced small concavities even when the aim was for a planar surface. Our findings suggest a surface structure dependency of the thermal signal, which is only observed at times with large temperature differences between air and snow. We were able to reproduce the hot-crust/cold-crust-phenomenon and relate it entirely to surface structure in a temperature-controlled cold laboratory. Concave areas cooled/warmed slower compared to convex areas when applying temperature differences between snow and air. This can be explained with increased emission or increased turbulent heat exchange between air and snow at convex areas. Thermal videos suggest that such processes influence the snow temperature within seconds. Our findings show the limitations of the use of a thermal camera for pit-wall temperatures; at interesting times, i.e. large gradient between air and snow, the interaction of snow pit and atmospheric temperatures will be enhanced. At interesting areas, i.e. crusts or other heterogeneities, we were not able to produce a homogenous snow pit surface and non-internal gradients will appear at the exposed surface. The immediate reaction speed of the snow pit temperature with the atmosphere complicates the capture of the internal thermal structure of a snowpack even with thermal videos. Instead, the shown structural dependency of the IR signal may be used to detect structural changes of snow, e.g. caused by kinetic metamorphism. The IR signal can also be used to measure near surface temperatures in a homogenous new snow layer.}, keywords = {Snow profile, infrared image, thermal structure}, author = {Schirmer, M. and Jamieson, B.} } @proceedings { 302, title = {Measurements of triggering stress transmitted through the upper snowpack}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {In the majority of fatal avalanches, skiers and snowmobilers apply load to the snow cover that triggers the initial failure in a weak layer. Understanding how the stress due to the dynamic surface load transmits through the snow cover can help people avoid situations where they can trigger avalanches. Capacitive sensors were used to measure this dynamic stress within the mountain snow cover. The sensors were used on 33 separate field days to collect over 6,500 measurements with loading by skiers, snowmobiles, falling skiers, people walking, drop hammer experiments and hand tapping on shovel blades as in some stability tests. The change in shape and magnitude of the induced stress was observed for three “typical” snow cover structures. Relatively soft snow allowed the specific levels of dynamic stress to penetrate deeper into the snow cover, thus increasing the probability of initiating a failure in a weak layer. Whereas, supportive surface layers spread the stress out laterally and decreased the depth to which specific levels of stress penetrated. We described the snow cover for the experiments according to a bridging index which allowed us to analyze the snow cover necessary to effectively spread the induced stress from a “typical” skiing turn and the uphill passage of a snowmobile. Using consistent and repetitive dynamic loading with a “drop hammer” device, more stress was observed in a fully isolated column of snow compared to unisolated snow. This yielded information about the bridging ability of varying snow stratigraphies. In summary, we present data describing how stress from human triggers penetrates the snow cover. }, keywords = {Stress, localized dynamic loading, snow properties, snow stability evaluation, bridging}, author = {Thumlert, S. and Jamieson, B.} } @proceedings { 299, title = {On estimating avalanche danger from simulated snow profiles}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {Estimating avalanche danger is the primary goal of avalanche warning services. Typically avalanche danger is estimated based on a variety of information such as manual snow profiles, avalanche observations as well as weather data. However, this required information is often not available especially in data sparse areas. It has been shown that coupled snow cover and numerical weather prediction models can provide such information on the snow cover. For this study we simulated the snow cover for three elevation bands – alpine, treeline, below tree-line – at Glacier National Park, B.C., Canada for the winter season 2012-2013 between December and March. Snow cover simulations were performed using the Swiss snow cover model SNOWPACK forced by weather data from the Canadian high-resolution numeric weather prediction model GEMLAM. Experienced forecasters estimated the regional avalanche danger (Low to Extreme) daily during the same period for the three elevation bands. Multivariate classification trees were used to estimate the avalanche danger from the simulated profiles. Classification trees were built using four parameters derived from the simulated profiles. These four parameters were the new snow amounts – 24-hours and 3-days – as well as measures for the likelihood of triggering and the expected avalanche size – based on Sk38 and the depth of a critical layer. A comparison of the avalanche danger estimated from the simulated profiles with the forecasted avalanche danger showed that the avalanche danger was estimated correctly with an accuracy of 76% for the alpine, 66% for tree-line and 72% below tree-line – overall accuracy 71%. Although the simulated avalanche danger tends to be slightly underestimated, especially for tree-line and below tree-line such a model chain can be a valuable tool for avalanche warning services especially for data sparse areas.}, keywords = {avalanche warning, avalanche danger, SNOWPACK, snow cover simulations, data sparse areas.}, author = {Bellaire, S. and Jamieson, B. } } @proceedings { 297, title = {Spatial predictions of surface hoar and crust formation}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {Understanding the distribution of critical snowpack layers over terrain is important to assess the avalanche hazard. Two common critical layers, surface hoar and melt-freeze crusts, form near the snow surface under specific weather conditions. In this study we modelled the distribution of such layers on a regional scale using forecasted weather data. To calibrate the models we measured the crystal size of surface hoar and the thickness and hardness of melt-freeze crusts at six study sites in the Columbia Mountains of British Columbia. We also tracked buried layers at these sites with weekly snow profiles. Surface hoar formation was modelled with the latent heat flux and melt-freeze crusts with a semi-physical model using radiation, temperature and precipitation data. Layers were also modelled with the snow cover model SNOWPACK. Forecasted weather data were used to map the formation of surface hoar and crusts on 2.5 and 15 km grids across the Coast, Columbia and Rocky Mountains. These predictions were compared to observations made by avalanche professionals at over 100 study plots. The model identified regions where surface hoar and melt-freeze crusts formed (presence or absence of a layer) and areas where the formation was more developed (indicated by surface hoar size and crust hardness and thickness). By coupling weather and snowpack models, spatial predictions of these critical layers could help forecasters assess avalanche hazard in data sparse areas. }, keywords = {surface hoar, melit-freeze crusts, formation, evolution, avalanche forecasting, snowpack stratigraphy, snowpack properties}, author = {Horton, S. and Schirmer, M. and Jamieson, B.} } @proceedings { 301, title = {Validating a relationship between avalanche runout distance and frequency}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {Statistical runout models such as the alpha-beta or Runout Ratio can provide good estimates of extreme avalanche runout, but do not describe more frequent runout distances, such as ten or thirty-year events. These boundaries are critical in many hazard mapping and analysis projects. This paper presents an assessment of a model which expresses return period as a function of runout distance. We created runout-return profiles from field trim line observations (38 paths) and occurrence records from transportation corridors (28 paths) in Canada. Over 250 points along these profiles were compared to model estimates. Model generated return periods fell mostly within the field observed range for 24 cases out of 143. Model generated return periods fell within 5 years of the 10, 15 and 30 year runout levels determined using occurrence records for 4 out of 31 cases. The model tended to overestimate return periods. }, keywords = {Statistical models, Runout Ratio, frequency, magnitude, Poisson, Gumbel, vegetation trim lines, avalanche runout, snow avalanches, runout zone, avalanche path}, author = {Sinickas, A. and Jamieson, B.} } @proceedings { 298, title = {Weather preceding deep slab avalanches}, year = {9999}, note = {Abstract submitted.}, month = {7/10/2013}, address = {Grenoble, France}, abstract = {Deep slab avalanches release on persistent weak layers of facets, surface hoar, depth hoar, or poorly bonded crusts and are generally hard to forecast. They are triggered either naturally from weather or from localized dynamic loads (LDLs) such as skiers or snowmobilers. For natural deep slab avalanches, weather preceding the release plays a key role in formation; load from precipitation or wind transported snow applies higher stress on underlying persistent weak layers. Alternatively, warm temperatures or solar radiation can reduce slab stiffness allowing for an increased strain rate on buried weak layers. Deep slab avalanches that release from LDLs are caused by the increased stress applied to buried persistent weak layers. For some deep slab avalanches that release from stress induced by LDLs, preceding weather likely also plays a strong role. For this research, 48 deep slab avalanches were accessed in Western Canada between 1993 and 2013 to obtain information on the persistent weak layer and overlying slab. Weather parameters such as precipitation amount, daily minimum and maximum temperature, and wind speed and direction were obtained from the nearest weather station for the two weeks prior to release of the accessed avalanches. Results indicate that the accessed natural deep slab avalanches typically occurred from either rapid mass loading via precipitation and/or wind transported snow or from snowpack warming by solar radiation. For some of the releases triggered by LDLs, we speculate that rapid loading from precipitation or wind transported snow increased the stress on the persistent weak layers to the point where the LDLs were critical. We also speculate that warming reduced slab stiffness for some deep slab avalanches, allowing the stress from the LDLs to reach deeper in the snowpack and subsequently initiate a fracture in the buried persistent weak layers. Examples of such releases are discussed. Case studies of natural releases that likely occurred from precipitation loading, wind loading, and solar warming are described. A natural deep slab avalanche that likely released from precipitation loading received approximately 22 cm of snow during the day of release, along with further loading from wind transported snow. The natural release that likely occurred from wind loading received only 15 cm of snow over the preceding four days but up to another 90 cm from wind transported snow. The natural release from solar warming received only 9 cm of snow in the preceding five days from release but was on a south-facing slope and exposed to direct short-wave radiation during the day of release. }, keywords = {avalanche forecasting, deep slab avalanche, preceding weather, natural, spontaneous, localized dynamic loading, persistent weak layers}, author = {Conlan, M. and Jamieson, B.} } @proceedings { 295, title = {Does climate change affect avalanche activity? - a study at Rogers Pass, Canada}, year = {9999}, note = {Abstract submitted.}, month = {07/10/2013}, address = {Grenoble, France}, abstract = {Long-term changes of the climate system have been observed. It has been shown in recent years that short term changing atmospheric conditions influence the formation and evolution of the seasonal mountain snow cover and therefore can influence the avalanche hazard. To investigate the effect of longterm changes of the climate system on avalanche formation we analyzed homogenized weather data, i.e. air temperature and precipitation, from Rogers Pass (1340 m a.s.l.) as well as non-homogenized weather data from Mt. Fidelity (1905 m a.s.l.). Both weather stations are located in Glacier National Park, British Columbia, Canada. Avalanche data from the same region were recorded between 1965 and 2012 along the section of the Trans Canada Highway located within the park. Although not significant, the mean annual air temperature showed similar trends for the last decades as already found for the Northern Hemisphere (+0.5 °C Mt. Fidelity, +0.7 °C Rogers Pass). The largest increase of the monthly mean air temperature was found for the early winter months from November to January. A general decreasing trend of the solid precipitation ratio, i.e. more rain, was found during recent decades, especially for the early winter season from October to December. The increase in early season rain might have favoured the formation of early season rain crusts. The frequency of natural avalanches within Glacier National Park did not increase during the last decades – perhaps confounded by variations in explosive use – but a trend towards more avalanches in January and March was found which might be related to the formation of early season rain crusts and would therefore suggest a potential shift towards deeper instabilities.}, keywords = {climate change, avalanche activity}, author = {Bellaire, S. and Thumlert, S. and Jamieson, B. and Statham, G.} } @proceedings { 294, title = {Snowpack tests and their association with local avalanche danger}, year = {9999}, note = {Abstract submitted}, month = {07/10/2013}, address = {Grenoble, France}, abstract = {The regional avalanche bulletin is an expert assessment of the avalanche danger for a specific region. This rating can differ from the local avalanche danger for several reasons, including the size of the forecast region, which in Canada ranges from 100 to 30,000 km2 compared to the 10 km2 covered in a typical backcountry day. This study assesses the correlation between snowpack tests (rutschblock and compression tests including fracture character and release type) and the local and regional avalanche danger. The results were grouped for analysis by the dominant avalanche problem / situation of the day, e.g. loose dry, wet (loose and slab), wind slab, storm slab, persistent slab and deep slab. This paper presents observations of snowpack tests, local avalanche ratings and key avalanche problems, collected over 374 field days since the winter of 2009. These field days yielded 627 individual ratings for comparison with 621 compression tests and 44 rutschblocks. The snowpack tests were performed in a representative location and accompanied by a profile to identify the failure plane and slab properties. An earlier study with a much smaller dataset showed weak but significant correlations between snowpack test results and local danger. We expect that rutschblock tests, being larger and more representative of human-triggering, will correlate better with the local avalanche danger than compression tests. We also expect that snowpack test results will correlate better with the local avalanche danger rating than with the regional bulletin. The results of this study could be useful in the preparation of public avalanche bulletins.}, keywords = {avalanche danger, snowpack tests, regional bulletin, compression test, rutschblock test}, author = {Haladuick, S. and Jamieson, B.} } @article { 303, title = {Measurements and weather observations at persistent deep slab avalanches}, journal = {Cold Regions Science and Technology }, year = {9999}, keywords = {slab avalanche, persistent weak layer, cohesive slab, avalanche forecasting, snow stability, snow strength, preceding weather}, author = {Conlam, M. and Tracz, D. and Jamieson, B.} } @inproceedings { 304, title = {Relating avalanche activity to climate change and coupled ocean-atmospheric phenomena}, booktitle = {Davos Atmosphere and Cryosphere Assembly DACA-13}, year = {2013}, note = {Abstract only.}, month = {12/07/2013}, address = {Davos, Switzerland}, abstract = {Climate change is evident and long-term changes of the climate system have been observed. It has been shown that changing atmospheric conditions influence the formation and evolution of the seasonal mountain snow cover and therefore determine the avalanche hazard. For this study we analyzed weather data measured at two weather stations between 1965 and 2012 located in Glacier National Park, British Columbia, Canada as well as avalanche data from the same region, i.e. along the section of the Trans Canada Highway located within Glacier National Park. The mean annual air temperature showed similar trends for the last decades as already found for the Northern Hemisphere (+0.5 °C Mt. Fidelity, +0.7 °C Rogers Pass). The largest increase of the monthly mean air temperature was found for the early winter month from November to January. A decreasing trend of the solid precipitation rate, i.e. more rain events, was found for the early winter season (October to December) favouring the formation of early season rain crusts. This might be related to climate change induced warming during the last decade favouring more weaknesses deep in the snowpack and potentially more deep slab avalanches. The frequency of natural avalanches within Glacier National Park did not increase during the last decades, but a trend towards more avalanches in January and March was found which might be related to the formation of early season rain crusts and therefore a shift towards deeper instabilities. An increasing frequency of avalanche activity could be expected during winters associated with La Niña or the cold phase of the Pacific Decadal Oscillation (PDO). Winters where La Niña and the cold phase of the PDO are in phase showed higher avalanche activity.}, keywords = {climate change, avalanche activity, La Niña, PDO}, author = {Bellaire, S. and Jamieson, B. and Statham, G.} } @article { 293, title = {How surface warming affects dry-snow instability}, volume = {31}, year = {2013}, pages = {25,31}, abstract = {Warming is believed to be one of the most prominent causes of snow instability – although experimental evidence is rare. We know that – due to the low thermal conductivity of snow – warming at the snow surface rarely affects the weak layer temperature. In the case of dry-snow slab avalanches, instability is not due to weakening of the weak layer, but is believed to be due to increased deformation within the near-surface layers of the slab. Solar radiation can penetrate the surface and effectively reduce the stiffness of the upper layers. Changing slab properties directly affect snow instability in many ways. Recent field measurements provide insight into the processes believed to promote dry-snow instability. But still, field evidence is rare, which is also because the effects of surface warming are subtle and likely only promote instability during certain slab/weak layer conditions.}, keywords = {warming, dry snow, solar radiation, slab avalanche}, author = {Schweizer, J. and Jamieson, B. and Reuter, B.} } @article { 291, title = {Measurements of localized dynamic loading in a mountain snowpack}, journal = {Cold Regions Science and Technology }, volume = {85}, year = {2013}, pages = {94-101}, publisher = {Elsevier}, abstract = {In the majority of fatal avalanches, skiers and snowmobilers apply load to the snow cover which triggers the initial failure in a weak layer. Understanding how the stress due to the dynamic surface load transmits through the snow cover can help people avoid situations where they can trigger avalanches. Capacitive sensors were used to measure this stress within the mountain snow cover. The three main variables affecting stress transmission through the snow cover investigated in this paper are the type of loading, depth and snow cover stratigraphy. At specific depths, snowmobiles added more stress than skiers did, thus increasing the probability of initiating a fracture in a weak layer and releasing a slab avalanche. The increased penetration depth of snowmobiles into the snow cover compared to skiers was the primary reason for this increase in stress. A decrease in stress was observed with increasing depth. A decrease in stress was observed with increased snow cover hardness. Supportive surface layers created a ‘bridging effect’ that spread stress out laterally and decreased the depth to which it penetrated.}, keywords = {avalanche forecasting, snowpack stratigraphy, snowpack properties, snowmobile, skier, capacitive sensors}, URL = {http://dx.doi.org/10.1016/j.coldregions.2012.08.005}, author = {Thumlert, S. and Exner, T. and Jamieson, B. and Bellaire, S.} } @inproceedings { 288, title = {How do you stress the snowpack?}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {506-512}, address = {Anchorage, Alaska}, abstract = {In the majority of fatal avalanches, skiers and snowmobilers apply load to the snowpack which triggers the initial failure in a weak layer. Understanding how the stress from a dynamic surface load transmits through the snowpack can help people avoid situations where they can trigger slab avalanches. Capacitive sensors were used to measure this stress within the mountain snowpack. The three main variables affecting stress transmission through the snowpack investigated in this paper are the type of loading, depth and properties of the snowpack. A decrease in stress was observed with increasing depth. At specific depths, snowmobiles added more stress than skiers did, thus increasing the probability of initiating a fracture in a weak layer and releasing a slab avalanche. The increased penetration depth of snowmobiles into the snowpack compared to skiers is the primary reason for this increase in stress. Falling skiers added about 3 times more stress than typical skiing. Skiers added about 1.5 times more stress than snowboarders. A decrease in stress was observed with increasing depth. Supportive surface layers created a “bridging effect” that spread stress out laterally and decreased the depth to which it penetrated.}, keywords = {snowpack stratigraphy, stress, snowmobiler, skier, avalanche release}, author = {Thumlert, S. and Jamieson, B. and Exner, T.} } @inproceedings { 282, title = {Modelling surface hoar formation and evolution on mountain slopes}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {194-200}, address = {Anchorage, Alaska}, abstract = {Predicting the spatial distribution and persistence of surface hoar layers is a challenge to avalanche forecasters and backcountry recreationists. This study evaluates surface hoar size predictions made with empirical weather based models and discusses how buried layers change over time. Surface hoar layers were observed during the 2011-2012 winter at flat, north and south facing slopes in the Columbia Mountains. Two models were developed to predict crystal size, one using a constant growth rate and the other estimating vapour deposit from the surface energy balance. Weather station data and forecasted data from the GEM15 numerical weather prediction model were used to simulate the growth of layers over seven winters. Reasonable size predictions were made with growth rates of 2.1 and 2.6 mm per day (r2 = 0.44), although specific rates appeared to change with season. The surface energy balance model made good predictions of crystal size with real station data (r2 = 0.74) and reasonable predictions with the output of GEM15 (r2 = 0.49). Time series of shear frame and propagation saw test results were made from observations on a buried surface hoar layer that formed in February 2012. The large crystals in this layer showed a steady increase in shear strength while the potential for fracture propagation remained high. The results of this study show promise for modelling surface hoar formation and evolution in snow cover models. }, keywords = {surface hoar, avalanche forecasting, snowpack stratigraphy, persistence, weak snowpack layer}, author = {Horton, S. and Bellaire, S. and Jamieson, B.} } @inproceedings { 284, title = {Measurements at recent deep slab avalanches}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {55-61}, address = {Anchorage, Alaska}, abstract = {Hard-to-forecast deep slab avalanches can release unpredictably under diverse conditions ranging from storms to clear days to locally induced stress to the snowpack. For the formation of many natural avalanches, a point is reached where the mass loading of overlying snow overpowers the mechanical properties of the weak layer. This can occur from additional loading above the weak layer, such as from precipitation or wind loading. Furthermore, natural failure can occur from solar warming and temperature variations. External stresses applied to the snowpack from skiers, snowmobilers, and other forces can also trigger deep slab avalanches. We collected field measurements of the properties of the failure layers and slab load to determine trends and correlations between such variables. The failure planes were analyzed using the deep tap test, propagation saw test, shear frame tests, and hand hardness and the overlying loads were calculated using density measurements. Spatial variability across the crowns was also assessed by use of multiple profiles and tests. Deep tap tests consistently yielded sudden (Q1) fractures and the cut length in the PST was usually less than 60% of the column length when the fracture propagated to the end. Preliminary results on spatial variability indicate that DT and shear frame results tended to increase with slab depth at some deep slab locations and crown thickness typically varied substantially. Locations with a thin snowpack, such as near rocky cliffs, were likely trigger points for some of the deep slab avalanches.}, keywords = {deep slab avalanches, avalanche forecasting, snowpack tests}, author = {Conlan, M. and Tracz, D. and Jamieson, B.} } @inproceedings { 281, title = {Nowcast with a forecast – Snow cover simulations on slopes}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {172-178}, address = {Anchorage, Alaska}, abstract = {The snow cover model SNOWPACK simulates the snow cover formation and evolution based on meteorological parameters. In the past, these parameters were measured by automatic weather stations. Recently, SNOWPACK was also forced with data from numerical weather prediction models (NWP). In this case study we assess the capability of such a model chain to simulate critical layers, i.e. surface hoar and melt-freeze crusts for a virtual north and south-facing slope as well as a level study plot. Meteorological key parameters for the snow cover formation and evolution, e.g. precipitation, radiation, air temperature and relative humidity were measured and compared to the forecasted data to evaluate the performance of the NWP model. Systematic errors of the NWP model were corrected and SNOWPACK finally forced with the adjusted data. Monthly manual profiles observed between January and March – north, south, flat – during the winter of 2010-2011, were compared to the corresponding snow cover simulations. The simulated stratigraphy was found to be in good agreement with the observations. Presence and absence of critical layers – surface hoar and melt-freeze crusts – were modeled with an accuracy of 81%. The simulated snow height tended to be over-estimated for all aspects and the leveled site, especially in March on the south-facing aspect. Nevertheless, the model chain showed a good performance considering the source of the input data. This study showed that such a model chain could become a useful tool for avalanche warning services in the future, especially for data sparse areas.}, keywords = {SNOWPACK, snow cover modeling, avalanche warning, numerical weather prediction models, snow cover stratigraphy}, author = {Bellaire, S. and Jamieson, B.} } @inproceedings { 287, title = {Statistical avalanche runout models: How well can computers predict beta?}, booktitle = {International Snow Science Workshop}, volume = {2}, year = {2012}, month = {16/09/2012}, pages = {716-722}, address = {Anchorage, Alaska}, abstract = {We reviewed the performance of a 23 m and 30 m Digital Elevation Model (DEM) and Google Earth in predicting beta (β) points for statistical runout modeling. Our objective was to find the resolution of DEM that was comparable to field survey error. We compared predicted β against field-determined β for 30 paths, using a field survey error range approximated from several error and repeatability measures. We found that none of the digital methods predicted β entirely within the range; however the 23 m DEM and Google Earth performed best. The 23 m DEM was biased to more conservative (downslope) estimates. The data suggested that a resolution of less than 23 m was required to match the error of a field survey; however, higher accuracy data may justify using a coarser resolution digital model. Judgment involved with β placement was a major contributor to uncertainty in this study. }, keywords = {snow avalanches, avalanche runout, DEM, field survey, beta point, alpha point, }, author = {Sinickas, A. and Jamieson, B.} } @inproceedings { 285, title = {The Propagation Saw Test (PST): A review of its development, applications, and recent research}, booktitle = {International Snow Science Workshop}, volume = {2}, year = {2012}, month = {16/09/2012}, pages = {1047-1053}, address = {Anchorage, Alaska}, abstract = {The Propagation Saw Test (PST) method was developed independently in Switzerland and in Canada in 2005 and 2006. It was inspired partly by observations of fracture propagation in earlier cantilever beam tests, and was partly based on notched-specimen tests that are common in fracture mechanics research. The PST has been used - in various modified forms - for investigation and verification of both shear-fracture and weak layer collapse failure models, for spatial variability studies, and for real-world avalanche forecasting and instability assessment. Many PST research and development studies have been conducted over the last several years, and recently there has been some debate regarding the best methodology and interpretation or application of test results. For these reasons, and given the recent or forthcoming adoption and standardization of the PST method by a number of international avalanche associations, we feel that researchers and practitioners could benefit from a comprehensive review of the development of the PST, its applications, and recent research which makes use of it. In this paper, we briefly review peer-reviewed articles, conference papers and presentations, and academic theses related to: the general test configuration and its relationship to fracture mechanics; the results of field experiments designed to test the influence of column size, cut direction, and slope angle on the test method; observations of ‘critical’ cut lengths, independent of column size in standard and non-standard test geometries; the empirical relationship between snowpack parameters and PST results; the basis for the original and modified test dimensions and methods; the verification of the method and validation of its application to the initiation and propagation of fracture; its applications to other research problems, such as fracture mechanics and spatial variability.}, keywords = {PST, propagation saw test, fracture propagation, snowpack stratigraphy, avalanche forecasting}, author = {Gauthier, D. and Jamieson, B.} } @inproceedings { 286, title = {Tracking melt-freeze crust evolution}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {84-91}, address = {Anchorage, Alaska}, abstract = {Melt-freeze crusts are one of the most critical layers for slab avalanche formation. These layers usually undergo complex metamorphism and associated snow cover stability may increase or decrease over time. Typical field observations are of a subjective nature and hence tracking changes to these layers can be inconsistent amongst multiple observers. In order to improve the way melt-freeze crusts are observed we present three tracking systems used over the 2011-12 winter season: a set of quantitative measurements, a simple new crust index (CI), and the use of a thermal imager. During the winter season 2011-12, six melt-freeze crusts were tracked over time with these methods in the Columbia Mountains, British Columbia, Canada. The physical properties of a melt-freeze crust can be best described using a set of quantitative measurements - shear frame, push gauge and density – but these may be operationally impractical. The crust index consists of two parts: the first part describes the bonding at the upper and lower interface of a melt-freeze crust; the second part describes the internal lamination or bonding within the crust. In addition, a thermal camera was used to measure small scale temperature gradients. This allowed us to monitor changes in the temperature gradient over time above and below melt-freeze crusts.}, keywords = {melt-freeze crust, snowpack evolution, persistent weak layer, Columbia Mountains, thermal imaging, crust index}, author = {Buhler, R., Jamieson, B.} } @inproceedings { 283, title = {Using a thermal imager to quantify buried thermal structure in natural snow}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {269-276}, address = {Anchorage, Alaska}, abstract = {Avalanche researchers and practitioners have long measured snowpack tempera¬tures in snow pits with thermometers about 10 cm apart. This led to the assumptions that temperature gradients are smooth and that temperature changes are regular. For this study, we used a thermal imager in standard snow pits in the Canadian Rocky Mountains during two seasons between 2010 and 2012. We collected the first season of data in a very shallow, below treeline snowpack study plot, and the second season of data in a deeper, treeline study plot. Data included thousands of thermal images, as well as visual macro images of the snow crystals in each pit layer to monitor changes. We observed strong temperature gradients on the scale of individual snow crystals. We found that these small scale gradients correlated with future snow crystal changes. We also found that these gradients changed quickly with the weather, even at depth. This paper focuses on our most recent findings from the 2011-12 season, and describes our overall progress in extracting data from thermal images to use for research and forecasting. We use correlations to present very general relationships between thermal data, crystal size, and layer stability tests. We also present temperature and gradient changes at depth during a period of clearing. }, keywords = {thermal imaging, infrared imaging, avalanche forecasting, temperature gradient, snowpack stratigraphy }, author = {Shea, C. and Jamieson, B. and Birkeland, K.} } @inproceedings { 280, title = {Vulnerability: Caught in an avalanche – then what are the odds?}, booktitle = {International Snow Science Workshop}, volume = {1}, year = {2012}, month = {16/09/2012}, pages = {1-8}, address = {Anchorage, Alaska}, abstract = {Vulnerability is an essential component in qualitative and quantitative avalanche risk analyses. It is the probable consequences given that the element-at-risk is hit by or caught in an avalanche. Since consequences vary with avalanche characteristics, there is a level of vulnerability associated with each type or size of avalanche. The avalanche size classification based on destructive potential is well suited to classifying vulnerability into different levels. We review vulnerability for vehicles on roads, buildings as well as backcountry recreationists and workers. Quantitative vulnerability typically requires some data, although expert estimation can be used with or without data. Quantitative vulnerability has the advantage that it can be used in comparisons with other risks to determine if a risk is acceptable. For backcountry recreation, data from non-fatal injuries are limited, so most calculations of vulnerability for people use only the expected probability of death. Using Canadian accident data, we estimate the vulnerability (probability of death) to roughly 0.004 to 0.007 for a Size D2 avalanche (destructive scale) and ten times higher for a Size D3 avalanche. We show how balloon packs can change the vulnerability of recreationists, and include an example of how vulnerability can be used in an avalanche risk assessment for a worksite.}, keywords = {avalanche, vulnerability, risk, roads, buildings, recreation, probability of death, balloon packs, worksite }, author = {Jamieson, B. and Jones, A.S.T.} } @article { 275, title = {What if you know what is next? Asarc working on snow cover simulation in data sparse areas}, volume = {99}, year = {2012}, month = {01/2012}, pages = {50-51}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, keywords = {SNOWPACK, snowpack simulation, data sparse areas, GEM15}, author = {Bellaire, S.} } @phdthesis { 290, title = {Deep Snow Slab Avalanches}, year = {2012}, pages = {215}, school = {University of Calgary}, type = {MSc}, address = {Calgary}, abstract = {Deep slab avalanches are a unique and difficult-to-forecast natural hazard. This thesis analyzed a variety of data sources from southwestern Canada including two large databases and data collected at 27 recent deep slab avalanches. A statistical method based on non-exceedance probability of average slab thickness and weak layer age was developed to regionally define deep slab avalanches. Local weather preceding deep slab events was investigated to discriminate days with deep slab avalanches from those without. Snowpack characteristics and tests were analyzed to find similarities among deep slab avalanche events. Precipitation during days with deep slab avalanches was found to be significantly more than days without deep slab avalanches. The Propagation Saw Test (PST) and Deep Tap Test (DT) were found to be useful snowpack tests for identifying deep slab hazard. The failure layer of deep slab avalanches typically was softer, contained larger snow grains, and was less dense the either of its adjacent layers.}, keywords = {avalanche forecasting, slab avalanches, antecedent weather, snowpack tests, regional characterization }, author = {Tracz, D.} } @article { 289, title = {Estimating Extreme Avalanche Runout for the Columbia Mountains and Fernie Area of British Columbia, Canada}, journal = {Canadian Geotechnical Journal }, volume = {49}, year = {2012}, pages = {1309-1318}, abstract = {Extreme snow avalanche runout is typically estimated using a combination of historical and vegetation records as well as statistical and dynamic models. The two classes of statistical models (α – β and runout ratio) are based on estimating runout distance past the β-point, which is typically defined as the point where the avalanche slope incline first decreases to 10°. The parameters for these models vary from mountain range to mountain range. In Canada, α – β and runout ratio parameters have been published for the combined Rocky and Purcell Mountains and for the British Columbia Coast Mountains. Despite active development, no suitable tall avalanche path model parameters have been published for the Columbia Mountains or for the Lizard Range area around Fernie, BC. Using a dataset of 65 avalanche paths, statistical model parameters have been derived for these regions. }, keywords = {statistical runout estimation, snow avalanches, alpha-beta, runout ratio, runout zone, beta point}, URL = {http://www.nrcresearchpress.com/doi/abs/10.1139/t2012-079#.UI3EaWef0R8}, author = {Johnston, Katherine. and Jamieson, Bruce. and Jones, Alan} } @phdthesis { 279, title = {Field studies of snowpack stress and deformation due to surface loads and temperature effects}, year = {2012}, pages = {211}, school = {University of Calgary}, type = {PhD Thesis}, address = {Calgary, Alberta, Canada}, abstract = {Snow surface loads such as skiers and snowmobiles are the triggers of the slab avalanche in many avalanche accidents. In most cases a cohesive slab overlies a weaker layer. Slab avalanche release strongly depends on stresses reaching the weak layer. Daytime snow temperature changes also can have a substantial impact on the release process of natural and human-triggered slab avalanches. Daytime variations of the near-surface layers affect the stiffness and the creep of the upper snowpack on a slope. For this study, a method was developed to measure normal stresses in the snowpack due to surface loads. These surface loads were skiers and snowmobiles in field experiments and metal weights in cold lab experiments. During the outdoor skier stress experiments and the cold lab studies the effect of warming and cooling of the near-surface layers and the effect on normal stress distribution was investigated. The impact of daytime heating of the near-surface layers on snowpack creep was monitored in field experiments. Overall, normal stresses due to surface loads penetrated deeper into the snowpack with warming of the near-surface layers or decreasing layer stiffness. Snowmobiles affected the snowpack over a larger area and stresses penetrated the snowpack deeper than for skier loads. In the case of the skier loads the bending of the skis appeared to have a considerable effect on the normal stress distribution. Creep of the near-surface layers accelerated with solar daytime warming and also affected layers below the warming front.}, keywords = {avalanche forecasting, snowpack stratigraphy, daytime warming, stress, snowpack properties, localized dynamic load, skier stress}, author = {Exner, T.} } @article { 273, title = {Hot crust, cold crust}, volume = {30}, year = {2012}, pages = {28}, keywords = {infrared image, melt-freeze crust}, author = {Shea, C. and Jamieson, B. and Birkeland, K.} } @article { 278, title = {Research to improve forecasting for deep slab avalanches}, volume = {100}, year = {2012}, pages = {70-72}, keywords = {avalanche forecasting, deep slab, deep tap test, propagation saw test, PST}, author = {Conlan, M. and Jamieson, B.} } @article { 272, title = {The Propagation Saw Test: slope scale validation and alternative test methods}, journal = {Journal of Glaciology}, volume = {58}, year = {2012}, pages = {407-416}, abstract = {The propagation saw test (PST) is a recently developed snowpack test that enables assessment of the fracture propagation propensity of selected persistent weak-layer and slab combinations, which are known to release dry-slab avalanches. In this paper, we assess the slopescale accuracy of the standard PST method at validated sites of observed weak-layer fracture initiation, with or without propagation. We also report on experiments with alternative test methods and varying saw thicknesses. Results show the standard PST method is comparably accurate to other common snowpack tests in predictive skill when predicting propagation propensity on the slope scale. Although a slight but significant dependence on saw thickness was found, it did not affect the interpretation in our validation study. Alternative methods such as scaling the test column length with weak-layer depth or leaving the upslope end of the column attached to the surrounding snowpack did not improve slopescale accuracy and these tests were often more difficult to interpret.}, keywords = {avalanches, avalanche forecasting, snowpack test, fracture propagation, propagation saw test, snowpack stratigraphy}, URL = {http://www.igsoc.org/journal/58/208/j11J192.html}, author = {Ross, C.K.H. and Jamieson, B.} } @article { 274, title = {The Life of a Shallow Snowpack (poster)}, year = {2012}, URL = {http://webapps2.ucalgary.ca/~asarc/files/ShallowSnowPoster_Shea_Jan2012.png}, author = {Shea, C. and Jamieson, B. and Birkeland, K.} } @article { 266, title = {Use of a thermal imager for snow pit temperatures}, journal = {The Cryosphere}, volume = {6}, year = {2012}, pages = {287-299}, keywords = {thermal image, infrared, snow stratigraphy, temperature gradient}, URL = {http://www.the-cryosphere.net/6/287/2012/}, author = {Shea, C. and Jamieson, B. and Birkeland, K.} } @inproceedings { 245, title = {Estimating extreme avalanche runout for the Columbia Mountains, British Columbia, Canada}, booktitle = {5th Canadian Conference on Geotechnique and Natural Hazards}, year = {2011}, month = {15/05/2011}, address = {Kelowna, BC}, keywords = {extreme avalanche runout, statistical model, alpha-beta, runout ratio}, author = {Johnston, Katherine and Jones, Alan and Jamieson, Bruce} } @inproceedings { 246, title = {Regional comparison of old-deep slab avalanches}, booktitle = {5th Canadian Conference on Geotechnique and Natural Hazards}, year = {2011}, month = {15/05/2011}, address = {Kelowna, BC}, keywords = {deep slab avalanches, avalanche forecasting, snowpack statigraphy}, author = {Tracz, Dave and Bellaire, Sascha and Jamieson, Bruce} } @article { 259, title = {Arfi: Avalanche Research Forecasting Interface}, volume = {95}, year = {2011}, pages = {54-55}, keywords = {avalanche forecasting, geospatial interface, GEM15, GSWarm, weather stations, avalanche bulletins, webcams}, URL = {http://www.ucalgary.ca/asarc/arfi}, author = {Shea, C. and J. Floyer} } @article { 271, title = {A new thermal view}, volume = {98}, year = {2011}, pages = {36-39}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, keywords = {thermal photography, infra-red, temperature gradient, snowpack stratigraphy, heat flow}, author = {Shea, C. and Jamieson, B.} } @phdthesis { 265, title = {Estimating Extreme Snow Avalanche Runout for the Columbia Mountains and Fernie Area of British Columbia, Canada}, year = {2011}, pages = {139}, school = {University of Calgary}, type = {MSc thesis}, address = {Calgary}, abstract = {Extreme snow avalanche runout is typically estimated using a combination of historical and vegetation records as well as statistical and dynamic models. The two classes of statistical models (α – β and runout ratio) are based on estimating runout distance past the β-point, which is generally defined as the point where the avalanche slope incline first decreases to 10°. The parameters for these models vary from mountain range to mountain range. In Canada, α – β and runout ratio parameters have been published for the Rocky and Purcell Mountains and for the British Columbia Coastal mountains. Despite active development, no suitable tall avalanche path model parameters have been published for the Columbia Mountains or for the Lizard Range area around Fernie, BC. Using a dataset of 70 avalanche paths, statistical model parameters have been derived for these regions. In addition, the correlation between extreme and average snowfall values and avalanche runout is explored.}, keywords = {snow avalanche, extreme runout, alpha-beta, runout ratio, Fernie, Columbia Mountains, extreme value statistics}, author = {Johnston, K.S.} } @article { 263, title = {Forcing the snow-cover model SNOWPACK with forecasted weather data}, journal = {The Cryosphere }, volume = {5}, year = {2011}, pages = {1115-1125}, keywords = {avalanche forecasting, snowpack stratigraphy}, URL = {http://www.the-cryosphere.net/5/1115/2011/tc-5-1115-2011.html}, author = {Bellaire, S. and Jamieson, B. and Fierz, C.} } @phdthesis { 268, title = {Four Applied Methods for Spatial Visualization in Snow Avalanche Forecasting}, year = {2011}, pages = {153}, school = {University of Calgary}, type = {PhD}, address = {Calgary}, abstract = {This thesis presents four applied methods for seasonal snow observation with respect to avalanches. Previous avalanche-related spatial variation and scale studies have shown a clear need for observation and methods to focus on the scale of interest to human triggering. These methods have the common goal to reveal spatial variation of interest to avalanche formation and human triggering in an efficient, accessible manner. The four methods are: (1) A minimally destructive slope-scale sampling method, (2) A method to relate Google Earth terrain images to surface hoar formation in sparse trees, (3) A method of accessibly presenting complex GIS warming model data over real terrain, and (4) A method of measuring heat in the snowpack using a thermal imager. Despite their common goal of spatial visualization, each new method draws on a diff erent subset of background literature and employs very di fferent methods in development and use. Thus, each method is presented as a self-contained paper with independent results. Of note, these methods have all subsequently received active use, and conclusions from such use are discussed at the end of the thesis.}, author = {Shea, Cora} } @article { 255, title = {Some fundamentals of handheld snow surface thermography}, journal = {The Cryosphere}, volume = {5}, year = {2011}, pages = {55-66}, keywords = {thermography, snow emissivity, photographic angle, solid state greenhouse effect}, URL = {http://www.the-cryosphere.net/5/55/2011/}, author = {Shea, C. and Jamieson, B.} } @article { 262, title = {Sun effect on surface hoar illustrated by three case studies}, journal = {Cold Regions Science and Technology }, volume = {68}, year = {2011}, pages = {95-105}, abstract = {Three case studies demonstrate solar effects on surface hoar crystal size. These effects are presented via: (a) a comparison of night and day time crystal sizes and surface temperatures, (b) a comparison of crystal sizes over different times in one day, and (c) a spatial comparison of tree shadows and surface hoar presence. The three case studies include surface hoar size with overall area sample means from 0.2 mm to 10.3 mm and across the treeline and alpine elevation bands. Although sample locations include various aspects, most of the data are from east aspects. As previous studies have found difficulty explicitly linking physical shortwave and latent heat measurements with surface hoar growth and destruction, this paper takes an empirical approach. Through correlations between temperature and surface hoar size, we find that different processes dominate in alpine versus treeline areas. Also, previous work presents different opinions as to whether summed shortwave or maximum shortwave plays a more important role in surface hoar size change; here, we present data which show the maximum change in incoming direct shortwave affects surface hoar crystal size.}, keywords = {shorwave radiation, surface hoar}, URL = {http://dx.doi.org/10.1016/j.coldregions.2011.06.010}, author = {Shea, C. and Jamieson, B.} } @inproceedings { 258, title = {Scenario-specific observations for regional snow avalanche warnings}, booktitle = {5th Canadian Conference on Geotechnique and Natural Hazards}, year = {2011}, address = {Kelowna, BC}, abstract = {

Avalanche forecasters are increasingly formalizing a risk-based approach to analyze different avalanche problems or scenarios. Since public danger warnings in Canada apply to large regions, users must down-scale the danger using local field observations. We conducted a field study in the mountains of western Canada on over 175 days. On each field day, an experienced team rated the local avalanche danger, identified the avalanche scenario of most concern locally, and observed a standard set of over 20 field observations. New snowfall over a two-day period correlated with local danger in all scenarios, but otherwise a unique set of observations correlated best with local danger for each scenario. The results provide an evidence-based selection of specific local observations for potential use in regional snow avalanche warnings. The identified observations may help recreationists make better informed decisions.


*Presenting author: bruce.jamieson@ucalgary.ca 1-403-220-7479

}, keywords = {snow avalanche warnings, risk scenarios, field observations, snow avalanche forecasting}, author = {Gauthier, Dave and Jamieson, Bruce} } @proceedings { 237, title = {Characteristics of old-deep-slab avalanches}, year = {2010}, month = {17/10/2010}, pages = {148-154}, address = {Squaw Valley, California}, abstract = { Deep and old slab avalanches (ODS) are often hard-to-forecast. The size and destructive potential of ODS avalanches can be disturbing. As a starting point for a study of hard-to-forecast avalanches we define ODS avalanches based on a large dataset spanning the three main mountain ranges of western Canada: Coast, Columbia and Rocky Mountains. The definition is based on extreme slab depth and extreme age of the snowpack weakness that failed causing the avalanche. Our data did not reveal a difference in slope angle or aspect between the deep-old-slab avalanches (ODS) and “Other” avalanches. However, compared to Other avalanches, ODS avalanches were typically of greater size, involved less human triggering, released more often on crusts and weak layers of facets and tended to occur more often in early winter.


}, keywords = {deep slab avalanche, avalanche forecasting, snow cover stability, snowpack properties, snowpack instability tests}, author = {Tracz, D. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 235, title = {Estimating extreme avalanche runout for the Lizard Range, Fernie, British Columbia, Canada}, year = {2010}, month = {17/10/2010}, pages = {252-257}, address = {Squaw Valley, California}, abstract = { Identifying the extreme avalanche runout is an important part of public safety for development in mountainous areas. Extreme avalanche runout is typically estimated using a combination of historical and vegetation records as well as statistical and dynamic models. The two main types of statistical models (α – β and Runout Ratio) are based on predicting runout past the β-point, which is generally defined as the point where the slope angle first decreases to 10° while descending the slope. Statistical models are commonly used for avalanche hazard mapping in Canada; however, the existing models cover broad geographical areas and may not accurately predict runout in some development areas. Located in southeastern British Columbia, the Lizard Range is a sub-range of the Canadian Rocky Mountains. Numerous recreational and residential developments are located in this area including the City of Fernie. Likely because of the heavy snowfall in this area, residential development in mountainous terrain in this area is intense. Possibly due to the heavy snowfall in this area, the existing statistical models for the Canadian Rocky Mountains tend to underestimate extreme avalanche runout for this area when compared to field evidence of extreme runout. Using a data set of 28 avalanche paths with vertical drops greater than 350 m, we use the existing Canadian statistical models to show how these models underestimate extreme avalanche runout for the Lizard Range. }, keywords = {extreme avalanche runout, runout ratio, alpha-beta, runout estimation, snow avalanche}, author = {Johnston, K.S. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 238, title = {GSWarm: An example of making a GIS model for everyday use}, year = {2010}, month = {17/10/2010}, pages = {523-529}, address = {Squaw Valley, California}, abstract = {Modeling snow processes over terrain with a Geographic Information System (GIS) takes a specific set of skills and a lot of computer processing power and time. These factors are often at odds with how such a model would be used for, say, daily avalanche forecasting. We used the near-surface snow warming statistical and empirical model SWarm as a basis for designing a simple and fast GIS tool. This simple GIS-based warming model, called GSWarm, resulted from (a) published user comments on existing snow and avalanche computer tools, (b) published graphic design principles, and (c) direct forecaster feedback. Using GSWarm as an example, we present key ideas used to provide a simple interface to a complex GIS model, including: (1) Calculating many possible scenarios ahead of time, so hypothesis testing of different weather and snow conditions can be done quickly. (2) Allowing small previews of many results to be seen on one screen, for selection of specific conditions without using input boxes. (3) Providing scaling and visualization help to the user rather than giving a single final result. These ideas represent a unique perspective on snow and avalanche computer model design. }, keywords = {computer assisted forecasting, Geographic Information Systems (GIS), modelling}, author = {Shea, C. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 239, title = {Near-infrared photography to quantify temporal changes in melt-freeze crusts}, year = {2010}, month = {17/10/2010}, pages = {409-414}, address = {Squaw Valley, California}, abstract = {Objective quantification of snowpack stratigraphy is a difficult task, especially when multiple observers may be tracking changes over time. Properties such as grain type and size, though well defined by various snow observation guidelines, are often interpreted differently. One potential solution is the use of near infrared (NIR) photography to track the specific surface area (SSA) of a given layer. Processed images provide a quantitative measure of in-situ grain morphology free of any requirements for interpretation in the field. For the past two winters the Applied Snow and Avalanche Research Group at the University of Calgary has used NIR photography to track changes in and around buried melt-freeze crusts in the Columbia Mountains of western Canada. Eight crusts were tracked using both NIR and manual observations for periods ranging from 5 to 12 weeks. This paper describes the methods used and presents results from this study. Advantages of the method over traditional observations are also discussed, as are challenges encountered over the past two seasons. }, keywords = {specific surface area, crust evolution, near-infrared photography, snowpack stratigraphy}, author = {Smith, M. and Jamieson, B.} } @proceedings { 236, title = {On the sustainability and arrest of weak layer fracture in whumpfs and avalanches}, year = {2010}, month = {17/10/2010}, pages = {224-231}, address = {Squaw Valley, California}, abstract = { Recent theoretical and practical descriptions of weak layer fracture have focused on the echanics of achieving a state of propagation, which is assumed to be self-sustaining. Arrest of weak layer fracture has been addressed for shear-based models, but has often been overlooked for collapsing weak layers. Regardless of the failure mode, discrete weak layer crystals must fail in sequence during propagation. This means that the slab is responsible to ‘communicate’ the fracture laterally as part of the propagation process. This communication ability is lost, and weak layer fracture propagation should arrest, if the continuity of the slab is destroyed by a fracture through its thickness. Often this is the case, for example in perimeter slab fractures in whumpfs; however, these perimeter fractures are difficult to explain without considering weak layer collapse, slab bending, and the spatial variability of the slab. In addition, it is unclear how weak layer fracture continues to propagate despite the en-echelon slab fractures sometimes observed during avalanche release. We propose several simple mechanisms by which perimeter fractures in whumpfs may occur, how weak layer fracture may repeatedly advance beyond the en-echelon slab fractures, and how these processes could be linked. We argue that fractures should propagate downward through the slab, and investigate the interaction or competition between the weak layer and slab fractures that may determine the arrest condition. In addition, we propose that a sustainability term is required to properly describe propagation propensity. }, keywords = {fracture propagtion, fracture arrest, weak snowpack layer}, author = {Gauthier, D. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 240, title = {On surface warming and snow instability }, year = {2010}, month = {17/10/2010}, pages = {619-622}, address = {Squaw Valley, California}, abstract = {Warming is believed to be one of the most prominent causes of snow instability – although experimental evidence is rare. We know that – due to the low thermal conductivity of snow – warming at the snow surface rarely affects the weak layer temperature. In the case of dry-snow slab avalanches, instability is not due to weakening of the weak layer, but is believed to be due to increased deformation within the near-surface layers of the slab. Solar radiation can penetrate the surface and effectively reduce the stiffness of the upper layers. Changing slab properties directly affect snow instability in many ways. Whereas measurements have shown that the surface layers in fact creep more rapidly due to warming, field evidence is mostly lacking on how these changes affect snow instability. This might be because the effects of surface warming are subtle and/or only observable under certain slab/weak layer conditions. }, author = {Schweizer, J. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 234, title = {Use of thermal photography to measure snowpack properties}, year = {2010}, month = {17/10/2010}, pages = {24-30}, address = {Squaw Valley, California}, abstract = {Many snow processes are linked to snow temperature. A thermal photograph captures tens of thousands of surface temperature measurements in a single, powerfully visual image. Surface temperature directly drives surface hoar growth and near surface faceting, and it indirectly affects albedo and crust formation. We introduce this new application of thermography by presenting images (thermographs) and thermographic videos from winter 2010. Three different aspects are presented: (1) the link between surface temperature and surface hoar formation, (2) the spatial variation of temperatures on a pit wall, and (3) the effect of crystal type on conduction. Currently, due to cost and technical demands, thermography may remain primarily a research tool. However, thermography is a promising new technique that produces both quantitative and intuitively visual results. }, keywords = {heat conduction, surface hoar, thermal photography, thermal profile, infrared, emissivity}, author = {Shea, C. and Jamieson, B.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 232, title = {When to dig? Thoughts on estimating slope stability}, year = {2010}, month = {17/10/2010}, pages = {424-430}, address = {Squaw Valley, California}, abstract = {

Information about the snow cover stability is crucial for avalanche forecasting and for winter backcountry recreation. For a reliable estimation of snow cover stability at all levels of stability and over terrain many stability tests would be required. These tests are time consuming and therefore not practical for backcountry recreationists. Sampling strategy becomes important if spatial variability is considered as a key component of avalanche release. A recently proposed sampling strategy for slope stability estimation allows one to estimate the slope stability with a maximum of four compression tests. However, since backcountry recreationists as well as avalanche professionals during recreation rarely perform stability tests, we wade into this important and controversial question: to dig or not to dig? We review and discuss sampling strategies and methods from the perspective of experienced and less experienced recreationists. Factors were identified which increase or decrease the value of snow cover observations – which require digging – for recreationists in order to estimate the snow cover stability. These factors include experience level, local observations – which do not require digging – from previous days and the current day, ability to interpret observations over terrain and across spatial scales as well as cumulative knowledge of the snowpack. In conclusion, the question is not "To dig or not to dig?", but "When to dig?" – the latter question we try to answer.

 

}, keywords = {stability tests, sampling strategy, avalanche formation, snow cover stability, avalanche education, stability evaluation, field observations}, author = {Bellaire, S. and Jamieson, B. and Schweizer, J.} editor = {Osterhuber, R. and Ferrari, M.}, } @proceedings { 233, title = {Which obs for which avalanche type?}, year = {2010}, month = {17/10/2010}, pages = {155-161}, address = {Squaw Valley, California}, abstract = { At the 2004 ISSW, Roger Atkins proposed that—early in the terrain selection process—backcountry travellers could identify which types of avalanches were likely, e.g. wind slab, persistent slab, wet avalanche. These avalanche types are analogous to a set of scenarios in traditional risk analysis. Variations on Atkins’ approach have been incorporated into some public bulletins. The types of avalanches that dominate the danger ratings are called Avalanche Types/Characters/Threats/Concerns/ Situations/Problems by different groups. The latest Swiss brochure for recreation in avalanche terrain suggests different observations for the four different types of avalanche situations. To determine which observations are best for which types of avalanches, a field study was conducted in the winters of 2008-09 and 2009-10 in the Coast Mountains, Columbia Mountains and Rocky Mountains of western Canada. On each field day, an experienced field team rated the local avalanche danger, identified two dominant Avalanche Types and observed a standard set of over 20 quick field observations. The quick observations included avalanches, wind transported snow, snowfall, etc. For correlation analysis, we focussed on two distinct classes of Avalanche Types: 1) Persistent Slabs, as well as 2) Wind Slabs combined with Storm Slabs. While some observations correlated with the local danger when either class of avalanches dominated the danger rating, other observations correlated best when only one of these two classes dominated the local danger rating. These results may help bulletin writers recommend that recreationists focus on certain local observations for better informed decisions. }, keywords = {field observations, avalanche character, avalanche danger rating}, author = {Jamieson, B and Schweizer, J. and Statham, G. and Haegeli, P.} editor = {Osterhuber, R. and Ferrari, M.}, } @article { 242, title = {Spatial distribution of surface hoar crystals in sparse forests}, journal = {Natural Hazards and Earth System Sciences}, volume = {10}, year = {2010}, month = {06/2010}, pages = {1317-1330}, keywords = {surface hoar formation, radiation balance, long wave radiation, sky view}, URL = {http://www.nat-hazards-earth-syst-sci.net/10/1317/2010/nhess-10-1317-2010.html}, author = {Shea, C. and Jamieson, B.} } @article { 231, title = {Imitating nature's hazardous genius}, volume = {92}, year = {2010}, month = {04/2010}, pages = {54-57}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, keywords = {surface hoar formation}, author = {Elmer, K. and Shea, C.} } @book { 250, title = {Avalanche Accidents in Canada, Volume 5, 1996-2007}, year = {2010}, pages = {429}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, keywords = {avalanche accidents, snow avalanches, avalanche education}, author = {Jamieson, B, and Haegeli, P. and Gauthier, D.} } @article { 243, title = {Evaluating terrain based criteria for snow avalanche exposure ratings using GIS}, year = {2010}, note = {Poster presented at conference. Abstract online. Geophysical Research Abstracts. }, keywords = {avalanche terrain, GIS}, URL = {http://meetingorganizer.copernicus.org/EGU2010/EGU2010-8620-1.pdf}, author = {Delparte, D. and Jamieson, B. and Waters, N.} } @article { 230, title = {Modeling strength and stability in storm snow for slab avalanches}, journal = {Cold Regions Science and Technology }, volume = {62}, year = {2010}, pages = {107-118}, keywords = {Avalanche forecasting; snowpack stratigraphy; stability index; snow cover stability}, author = {Gauthier, D. and Brown C. and Jamieson, B.} } @article { 241, title = {Rate effect experiments on round-tipped penetrometer insertion into uniform snow}, journal = {Journal of Glaciology}, volume = {56}, year = {2010}, pages = {664-672}, keywords = {snow properties, snowpack stratigraphy, snowpack penetrometer, rate effects, compaction zone}, author = {Floyer, J.A. and Jamieson, J.B.} } @article { 204, title = {Star: An efficient snow point-sampling method}, journal = {Annals of Glaciology}, volume = {51}, year = {2010}, pages = {64-72}, publisher = {International Glaciological Society}, abstract = {

The changeable, variable, and fragile nature of snow creates unique sampling challenges. In this paper, we present Star: an efficient, field-usable sampling method for use in point-sampling spatial studies. This paper validates the accuracy of the Star method via a comparative Monte Carlo simulation using 1024 detailed samples of elevation data. As spatial snow studies generally want to find spatial continuity in layers and other properties, we used variogram ranges to compare the ability of four sampling methods to accurately reveal such spatial correlation. The other three methods compared to Star represent gridded, gridded random, and pure random methods, whereas Star can be called a linear random method. The simulation showed Star’s accuracy to be comparable to both gridded and gridded random methods. From this comparative process we introduce a new measure of appropriateness for sampling methods: the correct convergence on a variogram model, which we call correct spatial correlation detection. This directly measures how many sampled areas become correctly classified with either spatially correlated or non-correlated variance for a given variogram model fit. In this measure, Star performed equivalently to the other methods, and in correct convergence it performed equally to pure random sampling.

}, keywords = {point sampling, variogram, spherical model, spatial correlation}, URL = {http://www.igsoc.org/annals/v51/54/t54A028.pdf}, author = {Shea, C. and Jamieson, B.} } @article { 226, title = {Snowpack tests for assessing snow-slope instability}, journal = {Annals of Glaciology}, volume = {51}, year = {2010}, pages = {187-194}, publisher = {International Glaciological Society}, abstract = {

Information on snowpack instability is crucial for assessing avalanche risk in backcountry operations as well as for operational forecasting of the regional avalanche danger. Since slab avalanche release requires both fracture initiation and fracture propagation in a weak snowpack layer, field observations should ideally provide reliable information on the probability or propensity of both fracture processes. Even simple field observations that do not require digging a snow pit can provide useful information. Traditional snowpack tests include the shovel shear test, the shear frame test, the compression test (CT) and the rutschblock test (RB). Interpretation of the test results for the CT and RB has been improved by considering the appearance or type of the fracture in addition to the score. More recently, two tests have been developed that focus on fracture propagation rather than initiation: the extended column test (ECT) and the propagation saw test (PST). We compare the sensitivity, specificity and unweighted average accuracy of various stability tests. Comparative studies indicate that the RB, ECT and PST have comparable accuracy. For most test methods the unweighted average accuracy of a single test was 70–90% depending on the dataset. Test methods such as the RB, ECT and PST, which fracture an area large enough to include fracture propagation, are generally more accurate than test methods that fracture smaller areas (e.g. the CT). The threshold-sum method was also less accurate. Even with very experienced observers for the RB, ECT and PST an error rate of at least about 5–10% has to be expected. Performing a second, adjacent test on the same slope improves test reliability.

}, keywords = {snowpack tests, fracture initiation, fracture propagation, Rutschblock Test, Compression Test, Extended Column Test, Propagation Saw Test, spatial variability}, URL = {http://www.igsoc.org/annals/v51/54/a54a105.pdf}, author = {Schweizer, J. and Jamieson, B.} } @article { 244, title = {Some fundamentals of handheld snow surface thermography}, year = {2010}, keywords = {infrared radiation, snow profile, brightness temperature, snow surface temperature, infrared, thermal image}, URL = {http://www.the-cryosphere-discuss.net/4/1467/2010/}, author = {Shea, C. and Jamieson, B.} } @phdthesis { 229, title = {Testing Fracture Propagation Propensity for Slab Avalanche Forecasting}, year = {2010}, note = {MSc thesis }, pages = {179}, school = {University of Calgary}, type = {MSc}, address = {Calgary, Alberta}, abstract = {

The Propagation Saw Test (PST) is a recently developed field test for slab‐avalanche forecasting. It is designed to test the fracture propagation propensity of a buried weak layer and overlying slab. This thesis reports on two winter field seasons of experimental validation of the PST in the Columbia Mountains of British Columbia, in which nearly 800 PSTs, 200 Extended Column Tests (ECT), and 230 experimental short‐scaled PSTs were performed. The PST was found to be efficacious at predicting propagation propensity on the slope scale, with predictive skill often exceeding that of other standard snowpack tests. Compared to the ECT, the PST performed well in deeply buried weak layers where fracture initiation via surface loading was difficult. In deep slabs, where field validation was impractical, PST results were compared to forecaster’s expert ratings of propagation propensity. The PST was compared to regional avalanche activity and often appeared indicative of propagation propensity trends on the regional scale.

}, keywords = {fracture propagation, weak snowpack layer, avalanche forecasting, snowpack tests, propagation saw test, extended column test}, author = {Ross, C.} } @article { 209, title = {Using stability tests and regional avalanche danger to estimate the local avalanche danger}, journal = {Annals of Glaciology}, volume = {51}, year = {2010}, pages = {176-186}, publisher = {International Glaciological Society}, abstract = {Because public avalanche forecast regions in Canada are large, ranging from 100 km2 to more than 30,000 km2, there are often areas within each region where the current local avalanche danger differs from the forecast regional danger. Identifying areas where the local danger is higher or lower than the regional rating is useful for recreational backcountry travellers; for those with limited experience, however, this is not always practical. During four winters in the Columbia, Coast and Rocky Mountains of western Canada, field teams performed stability tests and undertook local avalanche danger assessments for comparison against the regional danger ratings. Significant correlations between stability test variables and the local avalanche danger, and between stability test variables and the difference between local and regional danger, indicate potential for improved evaluation of the local danger if stability test results are considered with the regional bulletin rating. Although our analysis shows that a single stability test result cannot reliably be used to estimate the local avalanche danger, it does identify circumstances under which stability tests can help backcountry travellers identify an area of locally higher avalanche danger. }, keywords = {snowpack stability tests, avalanche forecasting, snowpack stratigraphy, regional avalanche danger, local nowcast}, URL = {http://www.igsoc.org/annals/v51/54/a54a106.pdf}, author = {Bakermans, L. and Jamieson, B. and Schweizer, J. and Haegeli, P.} } @proceedings { 216, title = {Key field observations for supplementing and localizing the avalanche danger rating}, year = {2009}, note = {Abstract and presentation only for Workshop on  Avalanche forecasting: problems and future avenues }, month = {27/09/2009}, address = {Davos, Switzerland}, abstract = {Snow avalanche danger can vary considerably within forecast regions, especially large regions. Professionals and experienced recreationists routinely use the regional forecast along with local observations to estimate the local avalanche danger. However, some less experienced recreationists are unsure how to interpret the various field observations. To identify some key field observations, we conducted a field study during the winters of 2006-07 and 2007-08 in three distinct snow climates in western Canada: maritime, continental and transitional. Experienced observers rated the local avalanche danger and made 24 observations of weather, avalanche activity and simple manual snowpack tests such as the hand shear test and ski pole test. In all three snow climates, the regional danger rating was better correlated with the local avalanche danger than any single field observation. However, we sought local observations which could supplement and localize the regional forecast. Many of the weather variables correlated better with the regional danger rating than with the local rating, and hence were not useful for localizing the avalanche danger. The key local observations were wind deposits, snow rolls and whumpfs in the maritime snow climate, recent slab avalanching, whumpfs, the hand shear test and cracking at the skis in the transitional climate, and blowing snow, snow surface conditions and probing with the ski pole in the continental snow climate. Explanations will be offered as to why the specific key observations were better correlated with local danger in each snow climate. }, keywords = {avalanche danger rating, regional danger, local danger, field observations, scale}, author = {Jamieson, B.} } @proceedings { 215, title = {Predicting surface hoar spatial variability in sparse forests using shading in satellite imagery}, year = {2009}, month = {27/09/2009}, pages = {102-106}, publisher = {Swiss Federal Institute for Forest, Snow and Landscape Research WSL.}, address = {Davos, Switzerland}, abstract = {

Surface hoar size and location can help predict avalanche trigger points after burial. This paper presents an empirical model to predict the size of surface hoar at the small scale, i.e. less than 10 m, in sparsely forested areas. The model is based on 288 point samples of surface hoar crystals, and uses greyscale values in satellite imagery to map its predictions over a 40-to-100 m scale from a single point observation. When verified in a different surface hoar formation cycle, at a different location and aspect, with crystals sized to more than 7 mm, the model predicted the correct size to within 2 mm of actual size, for 70 percent of the 47 verification points. We present the physical basis for this model through night time surface temperature measurements and sky view photograph masks obtained with a wide angle lens. Beyond helping to describe the small scale variance of surface hoar in commonly skied areas of sparse trees in North America, it confirms processes that drive surface hoar formation anywhere. And although potentially applicable only to areas with trees and weather similar to those examined here, this work demonstrates that with the right conditions surface hoar size can be spatially predicted with reasonable accuracy.

}, keywords = {surface hoar, crystal size, crystal growth, sky view, satellite imagery, forest, shading}, author = {Shea, C. and Jamieson, B.} editor = {Schweizer, J. and van Herwijnen, A.}, } @proceedings { 213, title = {Simple calculations of avalanche risk for backcountry skiing}, year = {2009}, month = {27/09/2009}, pages = {336-340}, publisher = {Swiss Federal Institute for Forest, Snow and Landscape Research WSL}, address = {Davos, Switzerland}, abstract = {The avalanche risk from backcountry skiing and its dependence on the regional danger ratings have not been estimated—notably in North America. To get around this data gap, we have tried to calculate the risk using an event tree which breaks the avalanche risk to backcountry skiers into the probability of triggering, the probability of being caught in a triggered avalanche, and the probability of death if caught. An expert survey estimated the probability of triggering a potentially fatal avalanche while making fresh tracks in a trigger zone for each level of regional avalanche danger. A previous study found that 40% of people who trigger a potentially fatal avalanche are caught. Based on accident reports, the probability of being killed depends on the avalanche size, the distribution of which is known for skier-triggered avalanches in Canada. To calculate the daily risk, we modelled making fresh tracks in a specified number of trigger zones as an encounter probability. Based on our assumptions, a person can directly ski a dozen or so trigger zones in a day while the regional danger is Low or Moderate with comparable risk to kayaking. For a person skiing directly 5-10 trigger zones while the avalanche danger is Considerable, the daily risk is likely higher than kayaking and in the range of rock climbing or mountaineering.  }, keywords = {avalanche risk, recreation, avalanche danger, skier triggering, probability of death, triggering odds}, author = {Jamieson, B. and Schweizer, J. and Shea, C.} editor = {Schweizer, J., van Herwijnen, A.}, } @proceedings { 219, title = {The effect of daytime warming on snow creep}, year = {2009}, month = {27/09/2009}, pages = {271-275}, publisher = {Swiss Federal Institute for Forest, Snow and Landscape Research WSL}, address = {Davos, Switzerland}, abstract = {

Snowpack warming is, besides loading by precipitation and wind-transport, one of the major triggers contributing to natural avalanche release. Established release mechanisms for spontaneous slab avalanches strongly depend on deformation rates in weak layers, which are affected by temperature changes. Once a critical rate is exceeded snow exhibits strain softening and ultimately brittle fracture. Failure of a weak layer is an important prerequisite to slab avalanche release. Critical slope parallel deformation rates may be reached in weak layers on sufficiently steep slopes due to increased creep in the overlying slab, which is heated by solar radiation. Using time lapse photography during the transition from cold mornings to warm sunny afternoons, we monitored vertical and slope parallel displacements of markers on a vertical snow profile on steep slopes. In a case study we present time series of displacements that showed increased snowpack creep and slope parallel deformation rates during solar heating of the near surface layers.

}, keywords = {snow creep, solar radiation, warming, settlement, spontaneous avalanche release}, author = {Exner, T., Jamieson, B.} editor = {Schweizer, J. and van Herwijnen, A.}, } @proceedings { 220, title = {Tracking changes in buried melt-freeze crusts}, year = {2009}, month = {27/09/2009}, pages = {107-111}, publisher = {Swiss Federal Institute for Forest, Snow and Landscape Research WSL}, address = {Davos, Switzerland}, abstract = {

Melt freeze crusts are a frequent occurrence in the mid-latitudes, often forming in the snowcover due to rain or wet snow in the fall and insolation in the spring. Such crusts are frequently found at the bed surface of deep slab avalanches. Although faceting and weakening at the boundaries and in the interior of crusts under low temperature gradients has been documented, few long term systematic observations exist. This omission is potentially important, as an understanding of these processes may improve forecasting the strength of deep crusts. For the past two winter seasons, the University of Calgary Applied Snow and Avalanche Research group (ASARC) has monitored naturally occurring crusts in the Columbia Mountains of Western Canada. Properties such as grain form and size, density, temperature and hardness were observed on a weekly basis. Starting in the 2008-09 field season, the specific surface area (SSA) of three crusts was measured weekly using near infrared digital photography, resulting in 23 observations over two months including the transition to near-isothermal snow, where substantial structural changes were observed. This paper details these and other results.

}, keywords = {melt freeze crust, snowpack evolution, near-crust faceting, near infrared photography, temperature gradient}, author = {Smith, M. and Jamieson, B.} editor = {Schweizer, J., van Herwijnen, A.}, } @proceedings { 214, title = {Validating the Propagation Saw Test on the slope scale}, year = {2009}, month = {27/09/2009}, pages = {282-286}, publisher = {Swiss Federal Institute for Forest, Snow and Landscape Research WSL}, address = {Davos, Switzerland}, abstract = {

Over the past few seasons, the Propagation Saw Test (PST) has gained increasing acceptance in some guiding and highway operations in western North America. University of Calgary researchers continued to perform the PST throughout the 2009 winter season in order to further validate the test by building on a previous study. In addition, researchers experimented with column scaling in an attempt to reduce false-stable predictions previously reported for shallow soft slabs. In 2009, more than 600 PSTs were performed in close to 100 snow pits in the Columbia Mountains of British Columbia, Canada to supplement existing data from the previous two winter seasons. At 28 sites in 2009, more than 70 PSTs were performed on 34 layers where fracture propagation was observed (e.g. avalanches or whumpfs) or where fracture initiation was confirmed without propagation. This supplements the 47 sites and 95 tests available to previously validate the PST on the slope scale. An attempt to reduce false-stable predictions of the PST by scaling column length with layer depth below a meter is briefly discussed, supporting the standard test method. A recording standard for the PST is also presented.

}, keywords = {Propagation saw test, fracture propagation, slope scale, validation, regional scale, avalanche forecasting, snowpack stratigraphy}, author = {Ross, C. and Jamieson, B.} editor = {Schweizer., J., van Herwijnen, A.}, } @proceedings { 206, title = {Snowpack forecasting for areas of sparse observations}, year = {2009}, note = {Abstract only. }, month = {19/07/2009}, address = {Montreal, Quebec, Canada}, abstract = {

Forecasting for avalanche hazard is a difficult endeavor, requiring timely inputs of meteorological and snowpack data. Traditionally in Western Canada, snowpack observations have been provided on a near-daily basis by commercial ski operators, parks and government highway operations. There are, however, an increasing number of areas in use by recreationists which are not well-monitored and suffer from infrequent and sparse data. Such areas often suffer from a paucity of relevant meteorogical observations, further complicating the job of avalanche forecasters.

The SNOWPACK model was developed by the WSL Institute for Snow and Avalanche Research SLF and is presently used in an operational capacity for avalanche forecasting in Switzerland. Inputs of wind, temperature, precipitation as well as short and longwave radiation are used to forecast evolution of a number of characteristics of a stratified snowpack including snow depth and temperature, as well as density and grain type. For the past two winter seasons the Applied Snow and Avalanche Research Group at the University of Calgary (ASARC), in partnership with the Canadian Avalanche Centre (CAC) and Alberta Environment, has run SNOWPACK at a data sparse site in the Crowsnest Pass region of Southern Alberta. Both raw telemetry data and results of model runs are made available to forecasters at the CAC, who evaluate the utility of model output as a component in a decision support framework. Model results are compared with manual profiles several times each winter, with initial results showing good agreement with observations.

}, keywords = {snowpack modelling, avalanche forecasting, remote weather station, sparse observations}, author = {Smith, M. and Jamieson, B. and Fierz, C. and Lehning, M.} } @article { 222, title = {Predicting the fracture character of weak layers from snowpack penetrometer signals}, journal = {Cold Regions Science and Technology }, volume = {59}, year = {2009}, month = {11/2009}, pages = {185-192}, keywords = {snow penetrometer, fracture character, snowpack stratigraphy, avalanche forecasting, snowpack properties, snow hardness}, author = {Floyer, J and Jamieson, B.} } @article { 210, title = {SWarm: A simple regression model to estimate near-surface snowpack warming for back-country avalanche forecasting}, journal = {Cold Regions Science and Technology }, volume = {59}, year = {2009}, month = {11/2009}, pages = {133-142}, keywords = {avalanche forecasting, near-surface warming, diurnal warming, snowpack temperatures, solar radiation, surface energy balance}, author = {Bakermans, L. and Jamieson, B.} } @article { 223, title = {Regional danger ratings and the odds of triggering a potentially fatal avalanche}, volume = {89}, year = {2009}, note = {Slightly revised for The Avalanche Review 28(1), p.15, (2009). }, month = {07/2009}, pages = {56-58}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, keywords = {regional avalanche danger, skier triggering, probability of triggering, odds of triggering}, author = {Jamieson, B.} } @article { 221, title = {Guidelines for snow-slope instability tests, European Union Report 43386 for Triggering Instabilities in Materials and Geosystems, FP6.}, year = {2009}, month = {06/04/2009}, address = {Manali, India}, abstract = {

Information on snowpack instability is crucial for assessing avalanche risk in backcountry operations as well as for operational forecasting of the regional avalanche danger. Since slab avalanche release requires both fracture initiation and fracture propagation in a weak snowpack layer, field observations should ideally provide reliable information on the probability or propensity of both fracture processes. Even simple field observations that do not require digging a snow pit can provide useful information. Traditional snowpack tests include the shovel shear test, the shear frame test, the compression test (CT) and the rutschblock test (RB). The interpretation of the test results for the CT and RB has been improved by considering the appearance or type of the fracture – in addition to the score. More recently, two tests have been developed that explicitly focus on fracture propagation rather than initiation: the extended column test (ECT) and the propagation saw test (PST). We compare the sensitivity, specificity and unweighted average accuracy of various stability tests. The unweighted average accuracy was for most tests 70-90% depending on the diversity of the dataset. In other words, in at least about 10% of the cases the tests did not provide reliable results. Tests such as the RB, ECT and PST, which fracture an area large enough to include fracture propagation, are generally more accurate than tests which fracture smaller areas.

}, keywords = {stability tests, snowpack stratigraphy, avalanche forecasting, fracture initiation, fracture propagation, extended column test, propagation saw test, rutschblock test, compression test}, URL = {http://www.trigs.eu/wp-content/deliverable_441.pdf}, author = {Schweizer, J. and Jamieson, J.B.} } @article { 212, title = {Fracture propagation: Recent research and implications}, volume = {27}, year = {2009}, note = {Full article starts on page 28 of The Avalanche Review, April 2009 }, month = {04/2009}, pages = {28-29, 32}, publisher = {Amercian Avalanche Association}, keywords = {fracture propagation, extended column test, propagation saw test, weak layer collapse, shear fracture, avalanche forecasting, weak snowpack layer}, author = {Birkeland, K. and Schweizer, J. and Jamieson, B.} } @article { 225, title = {An update on applied snow and avalanche science: Selected papers from the 2008 International Snow Science Workshop}, journal = {Cold Regions Science and Technology }, volume = {59}, year = {2009}, pages = {103-105}, keywords = {avalanche forecasting, snowpack stratigraphy, FMCW radar, GPR, penetrometer, avalanche dynamics, avalanche rescue}, author = {Jamieson, B. and Schweizer, J. and Birkeland, K.} } @article { 211, title = {Field observations for estimating the local avalanche danger in the Columbia Mountains of western Canada}, journal = {Cold Regions Science and Technology }, volume = {58}, year = {2009}, pages = {84-91}, abstract = {

Snow avalanche danger can vary considerably within the forecast regions, especially large regions. Experienced recreationists routinely use the regional forecast along with local observations to estimate the local avalanche danger. However, some less experienced recreationists are unsure how to interpret the various field observations. To assess a systematic approach, we conducted a field study during the winters of 2006-07 and 2007-08 in the Columbia Mountains of western Canada. Experienced observers rated the local avalanche danger and made 24 observations of weather, avalanche activity and simple manual snowpack tests on approximately 130 location-days. Since the local danger was often rated separately for the elevation bands alpine, treeline, and below treeline, the observations could be applied to 272 individual local danger ratings. Fourteen of the potential predictors yielded significant rank correlations with the local avalanche danger. Reflecting their larger scale, many of the weather variables correlated better with the regional danger forecast than with the local rating. In contrast, some snowpack observations including the hand shear and ski pole test correlated better at the local scale than the regional scale. Classification trees using the regional rating plus three of the local observations exhibited a better agreement with the local danger rating than did the regional rating by itself.

}, keywords = {avalanche forecasting, snowpack tests, field observations, classification trees, avalanche danger, scale issues}, author = {Jamieson, B. and Haegeli, P. and Schweizer, J.} } @article { 208, title = {The role of moisture in surface hoar growth}, volume = {88}, year = {2009}, pages = {61-64}, keywords = {surface hoar, water vapour, diffusion, cloud, vapour pressure, saturation}, author = {Shea, C. and Jamieson, B.} } @proceedings { 52, title = {Observation and modeling of buried melt-freeze crusts.}, year = {2008}, month = {21/09/2009}, pages = {170-178}, abstract = {

Melt-freeze crusts often occur as a result of wet snow, rain or strong insolation. Past observations have revealed the formation of weak layers at their boundaries, even when the depth-averaged temperature gradient favours rounding. Research has, however, predominantly targeted temperature regimes dominated by kinetic growth. During the winter of 2007-2008 University of Calgary researchers undertook systematic observations of the early December melt-freeze crust that was present throughout much of Western Canada. The data gathered included ongoing measurement of the temperature gradientacross the crust, snow load and shear strength. These observations were used along with meteorological measurements to drive the Swiss SNOWPACK model, a physically based single column model which simulates the evolution over time of a number of microstructural and mechanical properties of the snowpack. We present here the observations from the first year, initial efforts to identify parameters with the greatest influence on mechanical properties and results from model simulations.

}, keywords = {melt-freeze crust, avalanche forecasting, snow stratigraphy, snowpack modeling}, author = {Smith, M. and Jamieson, B. and Fierz, C.} } @proceedings { 55, title = {Application and limitations of dynamic models for snow avalanche hazard mapping}, year = {2008}, month = {21/09/2008}, pages = {730-739}, address = {Whistler, BC, Canada}, keywords = {avalanche dynamics, basal friction, friction coefficient, Coulomb friction, runout estimation, hazard mapping}, author = {Jamieson, B. and Margreth, S. and Jones, A.} editor = {Campbell, C., Conger, S., Haegeli, P.}, } @proceedings { 59, title = {Avalanche weak layer prediction from penetrometer profiles}, year = {2008}, month = {20/05/2008}, pages = {161-168}, address = {Laval University, Quebec. Presse de l'Université de Laval, Québec}, keywords = {digital penetrometer, snow resistance, snowpack stratigraphy, avalanche forecasting, snowpack layers}, author = {Floyer, J. and Jamieson, B.} editor = {In Locat, J., D. Perret, D. Turmel, D. Demurs and S. Leroueil (eds.), }, } @proceedings { 60, title = {Field observations for localizing snow avalanche danger}, year = {2008}, month = {20/05/2008}, pages = {543-550}, address = {Laval University, Quebec. Presse de l'Université de Laval, Québec}, keywords = {field observations, avalanche danger, scale issues, spatial scale, avalanche forecasting}, author = {Jamieson, B. and Bakermans, L. and Haegeli, P.} editor = {In Locat, J., D. Perret, D. Turmel, D. Demurs and S. Leroueil (eds.)}, } @article { 203, title = {ASARC's experience with incident peer narratives}, year = {2008}, month = {12/2008}, pages = {48-49}, publisher = {Canadian Avalanche Association}, address = {Revelstoke, BC, Canada}, keywords = {incident, peer narrative, accident report, safety culture, reporting culture}, author = {Jamieson, B.} } @article { 33, title = {How To: Propagation Saw Test (PST)}, year = {2008}, month = {12/2008}, pages = {68-69}, publisher = {Canadian Avalanche Association}, address = {Revelstoke, BC, Canada}, keywords = {propagation saw test, PST, snowpack tests, fracture propagation, weak layer, avalanche forecasting}, author = {Ross, C. and Gauthier, D. and Jamieson, B.} } @article { 62, title = {An attempt to describe the mechanism of surface hoar growth from valley clouds. }, journal = {Cold Regions Science and Technology}, volume = {54}, year = {2008}, pages = {83-88}, keywords = {surface hoar, valley cloud, stratus cloud, cloud physics, vapour diffusion}, author = {Colbeck, S. and Jamieson, B. and Crowe, S.} } @proceedings { 42, title = {A solar warming model (SWarm) to estimate diurnal changes in near-surface snowpack temperatures for back-country avalanche forecasting.}, year = {2008}, pages = {306-314}, keywords = {short wave radiation, snowpack warming, solar radiation, surface energy balance}, author = {Bakermans, L. and Jamieson, B.} } @proceedings { 56, title = {Avalanche threats and mitigation measures in Canada}, year = {2008}, pages = {836-844}, keywords = {avalanche hazard, avalanche terrain, avalanche forecasting, land use, hazard mitigation, avalanche risk}, author = {Campbell, C. and Bakermans, L. and Jamieson, B. and Stethem, C.} } @proceedings { 53, title = {Comparing fracture propagation tests and relating test results to snowpack characteristics}, year = {2008}, pages = {376-385}, keywords = {propagation saw test, PST, extended column tests, ECT, fracture propagation, fractire initiation, slab thickness, avalanche forecasting}, author = {Ross, C. and Jamieson, B.} } @proceedings { 54, title = {Can field observations be combined systematically with the regional danger rating to estimate the local avalanche danger?}, year = {2008}, pages = {228-237}, keywords = {avalanche danger, avalanche forecasting, field observations, scale issues, spatial scale, regional danger, local danger}, author = {Jamieson, B. and Haegeli, P.} } @article { 45, title = {Conceptual design of a digital snowpack probe}, volume = {85}, year = {2008}, pages = {78-81}, keywords = {penetrometer, probe, snowpack stratigraphy, hardness, penetration resistance, piezoelectric sensor, avalanche forecasting}, author = {Morrison, T. and L'Heureux, C. and Mitchell, V. and Quartero, A.} } @article { 61, title = {Can solar warming contribute to dry slab avalanches? }, volume = {84}, year = {2008}, note = {Translated and reprinted in Avalanche Press, Japan Avalanche Network, Vol. 2, Nov. 2009. }, pages = {70-73}, publisher = {Canadian Avalanche Association, Revestoke, BC.}, keywords = {warming, dry slab avalanches, snow density, settlement, snow temperature}, author = {Exner, T. and Jamieson, B.} } @article { 63, title = {Dry-snow slab avalanche release revisited: shear vs. collapse? }, volume = {10}, year = {2008}, keywords = {avalanche release, fracture propagation, collapse, shear, weak layer}, author = {Schweizer, J. and Jamieson, B.} } @article { 64, title = {Evaluating a prototype field test for fracture and failure propagation in weak snowpack layers. }, journal = {Cold Regions Science and Technology}, volume = {51}, year = {2008}, pages = {87-97}, keywords = {fracture propagation, failure propagation, weak snowpack layer, avalanche forecasting, snowpack test, field test}, author = {Gauthier, D. and Jamieson, B.} } @article { 57, title = {Fracture propagation propensity in relation to snow slab avalanche release: Validating the Propagation Saw Test}, journal = {Geophysical Research Letters }, volume = {35}, year = {2008}, pages = {L13501}, keywords = {fracture propagation, weak snowpack layer, snow slab, avalanche forecasting, fracture arrest, snowpack test}, author = {Gauthier, D. and Jamieson, B.} } @misc { 202, title = {Field book reference card: PST and ECT tests}, year = {2008}, keywords = {PST, ECT, Propagation Saw Test, Extended Column Test, Reference card}, URL = {http://wcmprod2.ucalgary.ca/asarc/system/files/PST_ECT_ComboRefCard_081222.pdf}, author = {Ross, C. and Gauthier, D. and Jamieson, B.} } @misc { 41, title = {Field Book Reference Card: Propagation Saw Test (PST). }, year = {2008}, keywords = {Propagation saw test, PST, Field book reference card}, author = {Ross, C. and Gauthier, D. and Jamieson, B.} } @article { 58, title = {Influence of snowpack layering on human-triggered snow slab avalanche release}, journal = {Cold Regions Science and Technology}, volume = {54}, year = {2008}, pages = {176-182}, keywords = {snow stratigraphy, snow avalanche, avalanche formation, snow stability, skier triggering, numerical modeling}, author = {Habermann, M. and Schweizer, J and Jamieson, J.B.} } @phdthesis { 43, title = {Layer detection and snowpack stratigraphy characterisation from digital penetrometer signals.}, year = {2008}, school = {University of Calgary}, type = {PhD Thesis}, address = {Calgary}, author = {Floyer, J.} } @proceedings { 49, title = {Modeling short wave radiation penetration into the snowpack: What can we learn from near surface snow temperatures?}, year = {2008}, pages = {204-208}, author = {Fierz, C. and Bakermans, L. and Jamieson, B. and Lehning, M.} } @proceedings { 47, title = {Predictions of the Propagation Saw Test: Comparisons with other instability tests at skier tested slopes}, year = {2008}, pages = {408-414}, author = {Gauthier, D. and Jamieson, B.} } @proceedings { 51, title = {Predicting the fracture character of potential weak layers in penetrometer signals}, year = {2008}, pages = {195-208}, author = {Floyer, J.A. and Jamieson, B.} } @article { 66, title = {Review of spatial variability of snowpack properties and its importance for avalanche formation. }, journal = {Cold Regions Science and Technology}, volume = {51}, year = {2008}, pages = {253-272}, keywords = {snow cover, snow stratigraphy, snow mechanical properties, snow slope stability evaluation, avalanche formation, avalanche forecasting, spatial variability, skier triggering, numerical modeling, scale}, URL = {http://www.avalanche.org/~nac/NAC/techPages/articles/08_CRST_Schweizer_etal_spatvar.pdf}, author = {Schweizer, J. and Kronholm, K. and , Jamieson, B. and Birkeland, K.} } @article { 44, title = {Statistical runout modeling of snow avalanches using GIS in Glacier National Park, Canada}, journal = {Cold Regions Science and Technology }, volume = {54}, year = {2008}, pages = {183-192}, keywords = {snow avalanches, hazard mapping, geographic information systems, digital terrain model}, author = {Delparte, D. and Jamieson, B. and Waters, N.} } @article { 65, title = {Snowpack observations and fracture concepts for skier-triggering of dry-snow slab avalanches}, journal = { Cold Regions Science and Technology}, volume = {51}, year = {2008}, pages = {112-121}, keywords = {snow cover stratigraphy, snow stability evaluation, avalanche formation, avalanche release, skier triggering, stability test, fracture }, author = {Schweizer, J. and McCammon, I. and Jamieson, B.} } @proceedings { 50, title = {Shear strength and snowpack stability trends in non-persistent weak layers}, year = {2008}, pages = {939-947}, author = {Brown, C. and Jamieson, B.} } @proceedings { 46, title = {The effect of snowpack warming on the stress bulb below a skier}, year = {2008}, pages = {415-420}, keywords = {snowpack warming, stress bulb, skier triggering, avalanche forecasting, snowpack stratigraphy}, author = {Exner, T. and Jamieson, B} } @article { 67, title = {Verification of Canadian avalanche bulletins including spatial and temporal scale effects. }, journal = {Cold Regions Science and Technology}, volume = {51}, year = {2008}, pages = {204-213}, keywords = {avalanche forecasting, forecast verification, scale issue, spatial scale, temporal scale, avalanche danger}, author = {Jamieson, B. and Campbell, C. and Jones, A.} } @proceedings { 48, title = {Validation of the Propagation Saw Test near whumpfs and avalanches}, year = {2008}, pages = {16-21}, author = {Gauthier, D., C. Ross and B. Jamieson} } @article { 76, title = {A threshold sum approach to stability evaluation of manual snow profiles. }, journal = {Cold Regions Science and Technology}, volume = {47}, year = {2007}, pages = {50-59}, author = {Schweizer, J. and Jamieson, B.} } @phdthesis { 68, title = {Avalanche Terrain Modeling in Glacier National Park, Canada}, year = {2007}, school = {University of Calgary}, type = {PhD}, address = {Calgary, Canada.}, author = {Delparte, D.} } @phdthesis { 70, title = {A practical field test for fracture propagation and arrest in weak snowpack layers in relation to slab avalanche release}, year = {2007}, school = {University of Calgary}, type = {PhD}, address = {Calgary, Canada}, author = {Gauthier, D.M.} } @techreport { 71, title = {Current and future snow avalanche threats and mitigation measures in Canada. }, year = {2007}, institution = {Canadian Avalanche Association}, address = {Revelstoke, BC, Canada}, keywords = {avalanche hazards, avalanche threats, future trends, hazard mitigation}, author = {Campbell, C. and Bakermans. L. and Jamieson, B. and Stethem, C.} } @article { 73, title = {Explanation and limitations of study plot stability indices for forecasting dry snow slab avalanches in surrounding terrain.}, journal = {Cold Regions Science and Technology}, volume = {50}, year = {2007}, pages = {23-34}, institution = {Canadian Avalanche Association}, keywords = {avalanche forecasting, snowpack stratigraphy, stability index, spatial scale}, author = {Jamieson, B. and Zeidler, A. and Brown, C.} } @article { 78, title = {Fracture character in compression tests. }, journal = {Cold Regions Science and Technology}, volume = {47}, year = {2007}, pages = {60-68}, institution = {Canadian Avalanche Association}, keywords = {fracture character, pops, drops, compression test, avalanche forecasting, sudden planar, sudden collapse, resistant planar, progressive compression, non-planar break}, author = {van Herwijnen, A. and Jamieson, B.} } @article { 72, title = {Influence of slab properties on human-triggered snow slab avalanche release. }, volume = {9}, year = {2007}, pages = {115-21}, institution = {Canadian Avalanche Association}, keywords = {avalanche release, avalanche forecasting, slab properties, skier triggering, skier stress, shear stress, weak layer}, author = {Habermann, M., J. Schweizer and J.B. Jamieson} } @article { 74, title = {Snowpack properties associated with fracture initiation and propagation resulting in skier-triggered dry slab avalanches. }, journal = {Cold Regions Science and Technology}, volume = {50}, year = {2007}, pages = {13-22}, institution = {Canadian Avalanche Association}, keywords = {fracture initiation, fracture propagation, weak snowpack layers, avalanche forecasting, snowpack stability, snowpack stratigraphy}, author = {Van Herwijnen, A. and Jamieson, B.} } @article { 77, title = {Spatial variability of slab stability and fracture characteristics within avalanche start zones. }, journal = {Cold Regions Science and Technology}, volume = {47}, year = {2007}, pages = {134-147}, institution = {Canadian Avalanche Association}, author = {Campbell, C. and Jamieson,B. } } @article { 69, title = {The propagation saw test}, volume = {83}, year = {2007}, pages = {60-63}, institution = {Canadian Avalanche Association}, keywords = {propagation saw test, fracture propagation, avalanche release, avalanche forecasting, snowpack tests, weak layer, slab properties}, author = {Gauthier, D. and Jamieson, B.} } @proceedings { 95, title = {Understanding the propagation of fractures and failures leading to large and destructive snow avalanches: recent developments.}, year = {2006}, month = {23/05/2006}, institution = {Canadian Avalanche Association}, address = {Calgary, Alberta}, author = {Gauthier, D. and B. Jamieson} } @article { 75, title = {An update on digital penetrometer technology. }, volume = {79 }, year = {2006}, pages = {53-55}, institution = {Canadian Avalanche Association}, keywords = {digital penetrometer, snow resistance, penetration resistance, snowpack layers}, author = {Floyer, J.} } @proceedings { 89, title = {Can stability tests help recreationists assess the local avalanche danger? }, year = {2006}, pages = {468-477}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, keywords = {snowpack stability tests, avalanche forecasting, avalanche danger, regional avalanche bulletin, local nowcast}, author = {Jamieson, B. and J. Schweizer and P. Hägeli and C. Campbell} editor = {J.A. Gleason (editor)}, } @proceedings { 81, title = {Evaluating a prototype field test for weak layer fracture and failure propagation.}, year = {2006}, pages = {107-116}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Gauthier, D. and B. Jamieson} editor = {J.A. Gleason (editor), }, } @proceedings { 87, title = {Empirical analysis of snow deformation patterns below probe tips. }, year = {2006}, pages = {555-561}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Floyer, J. and B. Jamieson} editor = {J.A. Gleason (editor)}, } @proceedings { 92, title = {Evolving shear strength, stability and snowpack properties in storm snow. }, year = {2006}, pages = {15-21}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Brown, C. and B. Jamieson} editor = {J.A. Gleason (editor)}, } @article { 79, title = {Formation of refrozen snowpack layers and their role in slab avalanche release. }, journal = {Reviews of Geophysics }, volume = {44}, year = {2006}, institution = {Canadian Avalanche Association}, keywords = {snow, avalanche, crystal growth, melt-freeze crust, stratigraphy, grain bonding}, author = {Jamieson, B.} } @article { 96, title = {Infrared communications with dataloggers. }, volume = {76}, year = {2006}, pages = {47-48}, institution = {Canadian Avalanche Association}, keywords = {infrared, digital communication, datalogger}, author = {Bakermans, L.} } @proceedings { 82, title = {Measuring near-surface snow temperature change over terrain}, year = {2006}, pages = {377-386}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Bakermans, L. and B. Jamieson} editor = {J.A. Gleason (editor) }, } @phdthesis { 80, title = {Near-Surface Snow Temperature Changes Over Terrain. }, year = {2006}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada. }, author = {Bakermans, L.} } @article { 94, title = {Puzzling over propagation propensity. }, volume = {76}, year = {2006}, pages = {44-46}, institution = {Canadian Avalanche Association}, author = {Gauthier, D.} } @article { 101, title = {Refinements of empirical models to forecast the shear strength of persistent weak layers, Part A: Layers of faceted crystals. }, journal = {Cold Regions Science and Technology}, volume = {44}, year = {2006}, pages = {194-205}, institution = {Canadian Avalanche Association}, author = {Zeidler, A. and Jamieson, B.} } @article { 102, title = {Refinements of empirical models to forecast the shear strength of persistent weak layers, Part B: Layers of surface hoar crystals.}, journal = { Cold Regions Science and Technology}, volume = {44}, year = {2006}, pages = {184-193}, institution = {Canadian Avalanche Association}, keywords = {avalanche forecasting, surface hoar, normal load, strength change, shear strength, empirical model}, author = {Zeidler, A. and Jamieson, B.} } @article { 97, title = {Reflections on near misses and safety culture.}, volume = {76}, year = {2006}, pages = {18-20}, institution = {Canadian Avalanche Association}, keywords = {safety culture, near miss, worker safety, reporting culture}, author = {Jamieson, B.} } @article { 99, title = {Snowpack properties associated with skier-triggering of dry slab avalanches. }, journal = {Natural Hazards Section NH7.02: Snow avalanche formation, avalanche dynamics and risk assessment. Geophysical Research Abstracts}, volume = {8}, year = {2006}, institution = {Canadian Avalanche Association}, author = {van Herwijnen, A. and Jamieson, B.} } @article { 100, title = {Spatial extrapolation of slab stability indices for snow avalanche forecasting.}, journal = {Natural Hazards Section NH7.02: Snow avalanche formation, avalanche dynamics and risk assessment. Geophysical Research Abstracts}, volume = {8}, year = {2006}, institution = {Canadian Avalanche Association}, author = {Jamieson, B. and Zeidler, A. and Brown, C.} } @proceedings { 83, title = {Spatial and time scale effects in Canadian avalanche bulletins.}, year = {2006}, pages = {394-492}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Jamieson, B., C. Campbell and A. Jones} editor = {J.A. Gleason (editor)}, } @proceedings { 84, title = {Surface hoar growth from valley cloud. }, year = {2006}, pages = {1-6}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Colbeck, S. and B. Jamieson} editor = {J.A. Gleason (editor)}, } @proceedings { 85, title = {Spatial clusters in slab stability and snowpack properties within avalanche start zones. }, year = {2006}, pages = {44-53}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Campbell, C., and B. Jamieson} editor = {J.A. Gleason (editor)}, } @proceedings { 86, title = {Snow slope stability evaluation using concepts of fracture mechanics.}, year = {2006}, pages = {211-218}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Schweizer, J., I. McCammon and B. Jamieson} editor = {J.A. Gleason (editor)}, } @proceedings { 88, title = {Spatial variability – so what? }, year = {2006}, pages = {365-377}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Schweizer, J., K. Kronholm, B. Jamieson and K. Birkeland} editor = {J.A. Gleason (editor)}, } @proceedings { 90, title = {SAWLEM: Slab and weak layer evolution model. }, year = {2006}, pages = {228-233}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Zeidler, A., B. Jamieson, T. Chalmers and G. Johnson} editor = {J.A. Gleason (editor)}, } @article { 98, title = {Towards a field test for fracture propagation propensity in weak snowpack layers. }, journal = {Journal of Glaciology}, volume = {52}, year = {2006}, pages = {164-168}, institution = {Canadian Avalanche Association}, author = {Gauthier, D. and B. Jamieson} } @proceedings { 91, title = {The effect of slab and bed surface stiffness on the skier-induced shear stress. }, year = {2006}, pages = {157-164}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Jones, A., B. Jamieson and J. Schweizer} editor = {J.A. Gleason (editor)}, } @proceedings { 93, title = {The Avaluator - a Canadian rule-based avalanche decision support tool for amateur recreationists. }, year = {2006}, pages = {254-263}, institution = {Canadian Avalanche Association}, address = {Telluride, CO.}, author = {Haegeli, P., I. McCammon, B. Jamieson, C. Israelson} editor = {J.A. Gleason }, } @proceedings { 111, title = {Assessing the probability of skier triggering from snow layer properties.}, year = {2005}, pages = {192-198}, institution = {Canadian Avalanche Association}, address = {Jackson Hole, Wyoming. USDA Forest Service, Fort Collins, CO }, author = {Schweizer, J., C. Fierz and B. Jamieson} } @article { 106, title = {Between a slab and a hard layer: Part 3 - Two field studies of facets growing above wet layers. }, volume = {72}, year = {2005}, pages = {48-51}, institution = {Canadian Avalanche Association}, keywords = {melt-freeze crust, latent heat, dry-on-wet faceting, faceted snow}, author = {Jamieson, B. and P. Langevin} } @article { 104, title = {Comparing regional forecasts of avalanche danger with local “nowcasts” – First results.}, volume = {74}, year = {2005}, pages = {56-59}, institution = {Canadian Avalanche Association}, keywords = {avalanche danger, spatial scale, avalanche forecast, lead time, local nowcast, regional forecast}, author = {Jamieson, B., A. Jones and J. Kelly} } @proceedings { 108, title = {Faceting above crusts and associated slab avalanching in the Columbia Mountains. }, year = {2005}, pages = {112-120}, institution = {Canadian Avalanche Association}, address = {Jackson Hole, Wyoming. USDA Forest Service, Fort Collins, CO }, author = {Jamieson, B. and P. Langevin} } @proceedings { 110, title = {Fracture character in compression tests.}, year = {2005}, note = {

Short video of a presentation on Pops and Drops http://vimeo.com/22219643

}, pages = {182-191}, institution = {Canadian Avalanche Association}, address = {Jackson Hole, Wyoming. USDA Forest Service, Fort Collins, CO }, keywords = {fracture character, pops, drops, compression test, avalanche forecasting, sudden planar, sudden collapse, resistant planar, progressive compression, non-planar break}, author = {van Herwijnen, A.F.G. and B. Jamieson} } @phdthesis { 107, title = {Fractures in weak snowpack layers in relation to slab avalanche release. }, year = {2005}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {PhD}, address = {Calgary, Alberta, Canada. }, author = {van Herwijnen, A.F.G.} } @article { 103, title = {High-speed photography of fractures in weak snowpack layers. }, journal = {Cold Regions Science and Technology}, volume = {43}, year = {2005}, pages = {71-82}, institution = {Canadian Avalanche Association}, abstract = { Abstract online at Geophysical Research Abstracts 6, 01710. }, keywords = {fracture, weak snowpack layer, slab avalanche release, fracture propagation}, author = {van Herwijnen, A.F.G. and Jamieson, B.} } @proceedings { 109, title = {Spatial variability of rutschblock results in avalanche start zones. }, year = {2005}, pages = {288-297}, institution = {Canadian Avalanche Association}, address = {Jackson Hole, Wyoming. USDA Forest Service, Fort Collins, CO }, author = {Campbell, C.P. and B. Jamieson} } @article { 105, title = {Using a checklist to assess manual snow profiles. (yellow flags) }, volume = {72}, year = {2005}, pages = {57-61}, institution = {Canadian Avalanche Association}, author = {Jamieson, B. and J. Schweizer} } @article { 114, title = {A nearest-neighbour model for forecasting skier-triggered dry-slab avalanches on persistent weak layers in the Columbia Mountains, Canada. }, journal = {Annals of Glaciology}, volume = {38}, year = {2004}, pages = {166-172}, institution = {Canadian Avalanche Association}, keywords = {avalanche forecasting, nearest neighbour, snowpack stratigraphy, snowpack stability index, persistent weak layer}, author = {Zeidler, A. and Jamieson, B.} } @article { 116, title = {Between a slab and a hard layer: Part 2 - The persistence of poorly bonded crusts in the Columbia Mountains. }, volume = {71}, year = {2004}, institution = {Canadian Avalanche Association}, keywords = {melt-freeze crust, facets, persistent weak layer, grain size, surface hoar}, author = {Jamieson, B.} } @article { 118, title = {Between a slab and a hard layer: Part 1 - Formation of poorly bonded crusts in the Columbia Mountains. }, volume = {70}, year = {2004}, pages = {48-54}, institution = {Canadian Avalanche Association}, keywords = {melt-freeze crust, faceted snow, dry-on-wet faceting, persistent weak layer}, author = {Jamieson, B.} } @proceedings { 121, title = {Computer assisted avalanche forecasting: human-triggered avalanches. }, year = {2004}, institution = {Canadian Avalanche Association}, address = { Vancouver, BC, Canada }, abstract = {Computer-assisted avalanche forecasting has become a valuable tool in some forecasting operations in Canada. Avalanche forecasting models are based on statistical, numerical and/or rule-based methods, but usually predict
natural rather than skier-triggered avalanches. A nearest neighbour forecasting model for skier-triggered avalanches on post storm weak layers was improved by adding snowpack properties including a stability index to meteorological variables. However, a skier stability index did not improve the forecasting success on storm snow instabilities. The best forecast could be achieved by using meteorological parameters. }, keywords = {avalanche forecasting, skier-triggering, nearest neighbours, snowpack properties}, URL = {http://www.westernsnowconference.org/proceedings/pdf_Proceedings/2004%20WEB/Zeidler,%20A.,%20and%20B.%20Jamieson_Computer-Assisted%20Avalanche%20For.pdf}, author = {Zeidler, A. and B. Jamieson} } @phdthesis { 119, title = {Forecasting skier-triggered avalanches in the Columbia Mountains of Canada. }, year = {2004}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {PhD}, address = {Calgary, Alberta, Canada. }, author = {Zeidler, A.} } @article { 112, title = {Heat flow from wet to dry snowpack layers and associated faceting.}, journal = { Annals of Glaciology }, volume = {38}, year = {2004}, pages = {187-194}, institution = {Canadian Avalanche Association}, keywords = {heat flow, snowpack stratigraphy, melt-freeze crust, faceted crystals, kinetic metamorphism, dry-on-wet faceting}, author = {Jamieson, B. and Fierz, C.} } @article { 115, title = {Modelling instability in the Swiss snow cover model SNOWPACK. }, journal = {Annals of Glaciology }, volume = {38}, year = {2004}, pages = {331-338}, institution = {Canadian Avalanche Association}, keywords = {snowcover modeling, snowpack instability, avalanche foroecasting, snowpack stratigraphy}, author = {Lehning, M. and Fierz, C. and Brown, R. and Jamieson, B.} } @article { 123, title = {More results on fracture characterization in compression tests. }, volume = {68}, year = {2004}, pages = {38-41}, institution = {Canadian Avalanche Association}, keywords = {fracture character, progressive compression, resistant planar, sudden planar, sudden collapse, break}, author = {van Herwijnen, A.F.G. and B. Jamieson} } @article { 113, title = {Statistical avalanche-runout estimation for short slopes in Canada. }, journal = {Annals of Glaciology}, volume = {38}, year = {2004}, pages = {363-372}, institution = {Canadian Avalanche Association}, author = {Jones, A.S.T. and B. Jamieson} } @article { 122, title = {Seismic measurement of fracture speed in a weak snowpack layer. }, journal = {Cold Regions Science and Technology }, volume = {40}, year = {2004}, pages = {41-45}, institution = {Canadian Avalanche Association}, keywords = {fracture speed, fracture propagation, weak snowpack layer, seismic, geophone, snowpack stratigraphy}, author = {Johnson, B.C. and B. Jamieson and R.R. Stewart} } @article { 117, title = {Small scale mapping of stability: If not, why not. }, volume = {71}, year = {2004}, pages = {45-49}, institution = {Canadian Avalanche Association}, keywords = {spatial scale, snowpack stability, stability tests, process scale, measurement scale}, author = {Campbell, C. and B. Jamieson and P. Haegeli} } @phdthesis { 120, title = {Spatial variability of slab stability and fracture properties in avalanche start zones. }, year = {2004}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada}, author = {Campbell, C.} } @proceedings { 133, title = {Snow stability measurements. }, year = {2003}, month = {22/11/2001}, pages = {317-331}, institution = {Canadian Avalanche Association}, edition = {CEMAGREF Editions}, address = {Grenoble, France}, author = {Schweizer, J. and B. Jamieson} } @article { 128, title = {A snow-profile-based forecasting model for skier-triggered avalanches on surface hoar layers in the Columbia Mountains of Canada. }, journal = {Cold Regions Science and Technology, Special issue, International Snow Science Workshop 2002 }, volume = {37}, year = {2003}, pages = {371-381}, institution = {Canadian Avalanche Association}, keywords = {surface hoar, snowpack stratigraphy, avalanche forecasting, strength change, normal load }, author = {Chalmers, T. and Jamieson, B.} } @proceedings { 141, title = {Avalanche Hazard Mapping in Canada}, year = {2003}, pages = {555-560}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Stethem, C., D. McClung, B. Jamieson and P. Schaerer} } @article { 130, title = {An update on fracture character in stability tests. }, volume = {66}, year = {2003}, pages = {26-28}, institution = {Canadian Avalanche Association}, keywords = {fracture character, compression test, progressive compression, resistant planar, sudden planar, sudden collapse, break}, author = {van Herwijnen, A. and B. Jamieson} } @proceedings { 137, title = {Contrasting stable and unstable profiles with respect to skier loading}, year = {2003}, pages = {499-501}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Schweizer, J. and B. Jamieson} } @proceedings { 132, title = {Estimating the average friction coefficient in a simplified avalanche dynamics model for short slopes in Canada. }, year = {2003}, pages = {309-316}, institution = {Canadian Avalanche Association}, address = {Edmonton, Canada}, author = {Jones, A.S.T. and B. Jamieson} } @proceedings { 136, title = {Estimating the strength of faceted snow layers for an avalanche forecasting model}, year = {2003}, pages = {130-137}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Zeidler, A. and B. Jamieson} } @proceedings { 140, title = {Forecasting shear strength and skier-triggered avalanches for buried surface hoar layers. }, year = {2003}, note = {Extended abstract }, pages = {138-140}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Chalmers, T. and B. Jamieson} } @article { 125, title = {Fracture propagation and resistance in weak snowpack layers. }, volume = {67}, year = {2003}, pages = {36-43}, institution = {Canadian Avalanche Association}, keywords = {fracture propagation, fracture resistance, weak snowpack layer, remote triggering, skier triggering}, author = {Jamieson, B.} } @proceedings { 138, title = {Interpreting fracture character in stability tests}, year = {2003}, pages = {514-520}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {van Herwijnen, A. and B. Jamieson} } @misc { 124, title = {Notes on Fracture Character scheme used by U of C ASARC Avalanche Research Group. }, year = {2003}, note = {See also van Herwijnen and Jamieson, 2003 in Avalanche News 66. }, institution = {Canadian Avalanche Association}, author = {van Herwijnen, A. and B. Jamieson} } @proceedings { 135, title = {Preliminary results from controlled experiments on the growth of faceted crystals above a wet snow layer}, year = {2003}, note = {Reprinted in Avalanche News 64, 32-37 }, pages = {337-342}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Jamieson, B. and A. van Herwijnen} } @article { 131, title = {Risk management for the spatial variable snowpack. }, volume = {66}, year = {2003}, pages = {30-31}, institution = {Canadian Avalanche Association}, keywords = {risk management, slab avalanche, spatial variability, uncertainty, margin of safety, trigger point}, author = {Jamieson, B.} } @article { 126, title = {Snow avalanche formation. }, journal = {Reviews of Geophysics}, volume = {41}, year = {2003}, pages = {1016}, institution = {Canadian Avalanche Association}, keywords = {snow avalanche formation, slab avalanche release, snowpack stratigraphy, avalanche forecasting, weak snowpack layer, snow metamorphism}, author = {Schweizer, J. and Jamieson, J.B. and Schneebeli, M.} } @article { 127, title = {Snowpack properties for snow profile analysis. }, journal = {Cold Regions Science and Technology, Special issue, International Snow Science Workshop 2002}, volume = {37}, year = {2003}, pages = {233-241}, institution = {Canadian Avalanche Association}, author = {Schweizer, J. and B. Jamieson} } @article { 134, title = {Snow avalanche hazard in Canada - A review. }, journal = {Natural Hazards, Special Issue on An Assessment of Natural Hazards and Disasters in Canada }, volume = {28}, year = {2003}, pages = {487-515}, institution = {Canadian Avalanche Association}, author = {Stethem, C., B. Jamieson, P. Schaerer, D. Liverman, D. Germain and S. Walker} } @proceedings { 139, title = {Spatial variability of slab stability in avalanche start zones}, year = {2003}, pages = {544-548}, publisher = {(J.R Stevens, editor), BC Ministry of Transportation, Victoria, BC}, institution = {Canadian Avalanche Association}, address = {Penticton, Canada}, author = {Stewart, K. and B. Jamieson} } @article { 129, title = {Spatial variability of stability and fractures in avalanche start zones: Results from the winter of 2002-03. }, volume = {66}, year = {2003}, pages = {23-25}, institution = {Canadian Avalanche Association}, keywords = {spatial variability, stability test, rutschblock test, fracture character, snowpack stability}, author = {Campbell, C. and B. Jamieson} } @phdthesis { 142, title = {Avalanche Runout Prediction for Short Slopes. }, year = {2002}, school = {University of Calgary }, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Canada}, author = {Jones, A.S.T.} } @article { 143, title = {Snow avalanche hazards and management in Canada: Challenges and progress. }, journal = {Natural Hazards }, volume = {26}, year = {2002}, pages = {35-53}, institution = {Canadian Avalanche Association}, author = {Jamieson, B. and C. Stethem} } @proceedings { 152, title = {Case study of a deep slab instability and associated dry slab avalanches}, year = {2001}, pages = {101-108}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Jamieson, B., T. Geldsetzer and C. Stethem} } @proceedings { 153, title = {Contrasting stability trends of two surface hoar layers in the Columbia Mountains}, year = {2001}, pages = {94-100}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Chalmers, T., B. Jamieson} } @article { 146, title = {Extrapolating the stability trends of buried surface hoar layers from a study plot. }, journal = {Cold Regions Science and Technology}, volume = {33}, year = {2001}, pages = {163-177}, institution = {Canadian Avalanche Association}, author = {Chalmers, T. and B. Jamieson} } @article { 151, title = {Evaluation of the shear frame test for weak snowpack layers. }, journal = {Annals of Glaciology}, volume = {32}, year = {2001}, pages = {59-69}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @proceedings { 157, title = {Estimating dry snow density from grain form and hand hardness. }, year = {2001}, note = {Reprinted in the Avalanche News 62, 45-51. }, pages = {121-127}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Geldsetzer, T. and B. Jamieson} } @article { 144, title = {Forecasting for deep slab avalanches. }, journal = {Cold Regions Science and Technology }, volume = {33}, year = {2001}, pages = {275-290}, institution = {Canadian Avalanche Association}, keywords = {deep slab avalanche, melt-freeze crust, faceted crystals, avalanche forecasting, shear frame stability index}, author = {Jamieson, B. and Geldsetzer, T. and Stethem, C.} } @proceedings { 154, title = {Field observations of skier-triggered avalanches}, year = {2001}, pages = {192-199}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Schweizer, J. and B. Jamieson} } @proceedings { 155, title = {Field data and theory for human-triggered "whumpfs" and remote avalanches. }, year = {2001}, note = {Reprinted in Avalanche News 61, 20-26 }, pages = {208-214}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Johnson, B.C., B. Jamieson and C.D. Johnston} } @proceedings { 156, title = {Forecasting factors for skier-triggered avalanches at a helicopter skiing operation. }, year = {2001}, pages = {184-191}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Jones, A.S.T, B. Jamieson and M. Wiegele} } @phdthesis { 149, title = {Forecasting shear strength and skier-triggered avalanches for buried surface hoar layers. }, year = {2001}, pages = {109}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada}, author = {Chalmers, T.} } @article { 147, title = {Meteorological forecasting variables associated with skier-triggered dry slab avalanches. }, journal = {Cold Regions Science and Technology }, volume = {33}, year = {2001}, pages = {223-236}, institution = {Canadian Avalanche Association}, author = {Jones, A.S.T. and B. Jamieson} } @inbook { 150, title = {Snow avalanches. }, booktitle = {A Synthesis of Geological Hazards in Canada. Bulletin 548}, year = {2001}, pages = {81-100}, publisher = {G.R. Brooks (ed.). Geological Survey of Canada}, institution = {Canadian Avalanche Association}, keywords = {snow avalanche, avalanche hazard, slab avalanche, avalanche forecasting, static defence}, author = {Jamieson, B.} } @article { 148, title = {Snow cover properties for skier-triggered avalanches. }, journal = {Cold Regions Science and Technology }, volume = {33}, year = {2001}, pages = {207-221}, institution = {Canadian Avalanche Association}, author = {Schweizer, J. and B. Jamieson} } @proceedings { 158, title = {Strength changes of faceted snowpack layers in the Columbia and Rocky Mountain snowpack climates in southwestern Canada. }, year = {2001}, note = {Reprinted in the Avalanche News 62, 10-21 }, pages = {86-93}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Johnson, G. and B. Jamieson} } @article { 145, title = {The formation of faceted layers above crusts. }, journal = {Cold Regions Science and Technology }, volume = {33}, year = {2001}, pages = {247-252}, institution = {Canadian Avalanche Association}, author = {Colbeck, S.C. and B. Jamieson} } @proceedings { 159, title = {The formation of faceted crystals above crusts. }, year = {2001}, note = {Extended abstract }, pages = {239}, publisher = {American Avalanche Association, PO Box 1032, Bozeman, Montana, 59771, USA}, institution = {Canadian Avalanche Association}, address = {Big Sky Montana}, author = {Colbeck, S.C. and B. Jamieson} } @article { 163, title = {Field studies of the cantilever beam test. }, volume = {18}, year = {2000}, pages = {8-9}, institution = {Canadian Avalanche Association}, keywords = {cantilever beam test, snowpack test}, author = {Johnson, B. Crane and Bruce Jamieson and Colin D. Johnston} } @phdthesis { 161, title = {Observations of Faceted Crystals in Alpine Snowpacks. }, year = {2000}, pages = {98}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada}, author = {Johnson, G.T.} } @phdthesis { 160, title = {Remotely Triggered Slab Avalanches. }, year = {2000}, pages = {98}, school = { University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada}, author = {Johnson, B.C. III.} } @article { 162, title = {Texture and strength changes of buried surface hoar layers with implications for dry snow-slab avalanche release. }, journal = {Journal of Glaciology }, volume = {46}, year = {2000}, pages = {151-160}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and J. Schweizer} } @article { 169, title = {Effects of surface warming on a dry snowpack. }, journal = {Cold Regions Science and Technology}, volume = {30}, year = {1999}, pages = {59-65}, institution = {Canadian Avalanche Association}, author = {Wilson, Adrian, Jürg Schweizer, Colin Johnston and Bruce Jamieson} } @article { 165, title = {Patterns in unexpected skier-triggered avalanches. }, volume = {58}, year = {1999}, note = { Also reprinted in The Avalanche Review 18(3) 4-7. }, pages = {7-17}, institution = {Canadian Avalanche Association}, keywords = {slab avalanche, skier triggering, avalanche terrain, remote triggering}, author = {Jamieson, Bruce and Torsten Geldsetzer} } @article { 164, title = {Skier triggering of slab avalanches: Concepts and research. }, volume = {18}, year = {1999}, pages = {8-10}, institution = {Canadian Avalanche Association}, keywords = {slab avalanche, skier triggering, group triggering}, author = {Jamieson, Bruce} } @article { 166, title = {The compression test - after 25 years. }, volume = {18}, year = {1999}, pages = {10-12}, institution = {Canadian Avalanche Association}, keywords = {compression test, snowpack stability test}, author = {Jamieson, Bruce} } @proceedings { 172, title = {Avalanche forecasting for transportation corridor and backcountry in Glacier National Park (BC, Canada). }, year = {1998}, pages = {238-244}, institution = {Canadian Avalanche Association}, author = {Schweizer, Jürg, Bruce Jamieson and David Skjönsberg} editor = {Erik Hestnes, Norwegian Geotechnical Institute, publication 203 }, } @article { 170, title = {Experience with microphotography of buried surface hoar. }, volume = {17}, year = {1998}, note = {Also presented at the Technical Meeting of the Canadian Avalanche Association, May 1998. }, pages = {6-8}, institution = {Canadian Avalanche Association}, keywords = {surface hoar, microphotography}, author = {Geldsetzer, Torsten and Bruce Jamieson and Colin Johnston} } @proceedings { 168, title = {Observations of buried surface hoar in British Columbia, Canada: section analysis of layer evolution and associated strength measurements.}, year = {1998}, pages = { 86-92}, publisher = {Stevens Pass Ski Area, P.O. Box 98, Skykomish, WA}, institution = {Canadian Avalanche Association}, address = {Sunriver, Oregon}, author = {Davis, Robert , Bruce Jamieson and Colin Johnston} } @article { 175, title = {Refinements to the stability index for skier-triggered slab avalanches.}, journal = { Annals of Glaciology }, volume = {26}, year = {1998}, pages = {296-302}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @misc { 174, title = {Regional snow avalanche activity and locations of known fatal accidents in Canada (1863-June 1997).}, year = {1998}, institution = {Canadian Avalanche Association}, author = {Jamieson, B. and G. Brooks} } @proceedings { 167, title = {Snowpack factors associated with strength changes of buried surface hoar layers}, year = {1998}, note = {Also, reviewed and revised for Cold Regions Science and Technology 30(1999), 19-34. }, pages = {74-85}, publisher = {Stevens Pass Ski Area, P.O. Box 98, Skykomish, WA}, institution = {Canadian Avalanche Association}, address = {Sunriver, Oregon}, author = {Jamieson, Bruce and Colin Johnston} } @article { 171, title = {Snowpack characteristics for skier triggering. }, volume = {55}, year = {1998}, note = {Also presented at the Technical Meeting of the Canadian Avalanche Association, May 1998. }, pages = {31-39}, institution = {Canadian Avalanche Association}, keywords = {slab avalanche, skier triggering, snowpack characteristics, snow slab properties, weak layer properties}, author = {Jamieson, Bruce and Colin Johnston} } @proceedings { 183, title = {Avalanche probing revisited. }, year = {1997}, note = {Also reprinted in Avalanche News 49, 16-19 }, pages = {295-298 }, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada. }, institution = {Canadian Avalanche Association}, address = {Banff, 118-125.}, author = {Auger, Tim and Bruce Jamieson} } @proceedings { 180, title = {Experience with stability evaluation for a surface hoar layer during winter 1995-96 at Rogers Pass, British Columbia, Canada.}, year = {1997}, pages = {118-125}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada. }, institution = {Canadian Avalanche Association}, address = {Banff, Canada }, author = {Schweizer, Jürg, David Skjönsberg and Bruce McMahon} } @proceedings { 173, title = {Improved probing for buried avalanche victims.}, year = {1997}, pages = { 211-218}, publisher = {Government of Canada, Ministry of Public Works 93-5/1997E}, institution = {Canadian Avalanche Association}, address = {Sault Ste. Marie}, author = {Jamieson, Bruce and Tim Auger. } } @article { 178, title = {Mechanisms for strength changes of buried surface hoar layers. }, volume = {53}, year = {1997}, pages = {7-11}, institution = {Canadian Avalanche Association}, keywords = {surface hoar, weak snowpack layer, snowpack stratigraphy, load, overburden, crystal penetration, superstratum, substratum}, author = {Jamieson, Bruce and Colin Johnston} } @proceedings { 179, title = {Observations on buried surface hoar- persistent failure planes for slab avalanches in British Columbia, Canada}, year = {1997}, pages = {81-85}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada. }, institution = {Canadian Avalanche Association}, address = {Banff, Canada }, author = {Davis, R., B. Jamieson, J. Hughes and C. Johnston} } @proceedings { 181, title = {Preliminary results on controlled shear experiments. }, year = {1997}, pages = {195-197}, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, institution = {Canadian Avalanche Association}, address = {Banff, 118-125.}, author = {Schweizer, Jürg.} } @proceedings { 182, title = {The compression test for snow stability. }, year = {1997}, note = {Also abridged for Avalanche News 49, 12-15 }, publisher = {Canadian Avalanche Association, Revelstoke, BC, Canada}, institution = {Canadian Avalanche Association}, address = {Banff, 118-125.}, author = {Jamieson, Bruce and Colin Johnston} } @article { 176, title = {The facet layer of November 1996.}, volume = {52}, year = {1997}, pages = {10-15}, institution = {Canadian Avalanche Association}, keywords = {faceted crystal, weak snowpack layer, melt-freeze crust, Columbia Mountains, persistent weak layer}, author = {Jamieson, Bruce and Colin Johnston} } @article { 177, title = {Visible changes in buried surface hoar over time. }, volume = {52}, year = {1997}, pages = {16-17}, institution = {Canadian Avalanche Association}, keywords = {surface hoar, microphotography, persistent weak snowpack layer}, author = {Geldsetzer, Torsten and Bruce Jamieson and Colin Johnston} } @phdthesis { 184, title = {Avalanche prediction for persistent snow slabs. }, year = {1995}, pages = {275}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {PhD}, address = {Calgary, Alberta, Canada}, author = {Jamieson, Bruce} } @article { 185, title = {Interpreting rutschblocks in avalanche start zones. }, volume = {46}, year = {1995}, pages = {2-4}, institution = {Canadian Avalanche Association}, keywords = {rutschblock test, snowpack stability test, avalanche forecasting, snowpack stratigraphy}, author = {Jamieson, Bruce and Colin Johnston} } @proceedings { 186, title = {Monitoring a shear frame stability index and skier-triggered slab avalanches involving persistent snowpack weaknesses}, year = {1995}, pages = {14-21}, institution = {Canadian Avalanche Association}, author = {Jamieson, Bruce and Colin. Johnston} } @proceedings { 188, title = {Five Mountain Parks Highway Avalanche Study. }, year = {1994}, pages = { 72-79}, institution = {Canadian Avalanche Association}, author = {Stethem, C., P. Schaerer, B. Jamieson, J. Edworthy} } @article { 187, title = {Transceivers and Avalanche Safety. }, volume = {42}, year = {1994}, pages = {8}, institution = {Canadian Avalanche Association}, keywords = {avalanche transceivers, avalanche beacons, survival rate, survival time}, author = {Jamieson, Bruce} } @proceedings { 193, title = {Experience with rutschblocks }, year = {1993}, note = {Slightly abridged for Avalanche Review 11(2), 1, 4-5 }, month = {4/10/1992}, pages = {150-159}, institution = {Canadian Avalanche Association}, address = {Breckenridge, Colorado}, abstract = {

During the winters of 1990-1992, rutschblock technique and limitations, variability and precision of rutschblock scores, and applications of rutschblocks to slab stability evaluation were studied in the Cariboo and Monashee Mountains of western Canada. The time required for each test was, under many conditions, reduced to 10 minutes or less by using cords, specialized saws or the tails of skis to cut the two sides and the upper wall of the rutschblock. The median rutschblock score was 4 or less on most days when one or more large dry natural slab avalanches were reported by helicopter skiing guides operating within 30 km of the study area. Also, median rutschblock scores were 4 or less near slabs that had been ski-released and individual scores up to 5 were recorded near recently ski-released slabs. On slopes of 20° to over 40°, median rutschblock scores correlate well with a Swiss stability index; however, rutschblock scores on slopes below 20° are inconsistent with the correlation suggesting a minimum angle for rutschblocks of approximately 20°. In spite of natural variability of rutschblock scores on a particular slope, decreasing the slope angle by 10° tended to increase the rutsehblock score by 1. A tendency for higher and more variable scores was noticed near the top of several slopes.

}, keywords = {rutschblock test, ski block test, spatial variability, slope angle effect}, author = {Jamieson, Bruce and Colin. Johnston} } @article { 191, title = {A progress report on studies of persistent slab instabilities. }, volume = {40}, year = {1993}, pages = {10-13}, institution = {Canadian Avalanche Association}, keywords = {persistent weak snowpack layer; persistent instability; slab avalanche}, author = {Jamieson, Bruce and Colin Johnston} } @article { 190, title = {Rutschblock precision, technique variations and limitations. }, journal = {Journal of Glaciology }, volume = {39}, year = {1993}, pages = {666-674}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @article { 192, title = {Shear frame stability parameters for large-scale avalanche forecasting. }, journal = {Annals of Glaciology}, volume = {18}, year = {1993}, pages = {268-273}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @article { 189, title = {Snow slab layers and stability: a summary of some recent research and experience. }, volume = {41}, year = {1993}, note = {Reprinted in The Avalanche Review 12(5), 1-3 and in ACMG News 4, Winter 1994, 4-5 }, pages = {2-3}, institution = {Canadian Avalanche Association}, author = {Jamieson, Bruce} } @article { 196, title = {A fracture-arrest model for unconfined dry slab avalanches. }, journal = {Canadian Geotechnical Journal}, volume = {29}, year = {1992}, pages = {61-66}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @article { 195, title = {Rutschblock technique and interpretation. }, volume = {37}, year = {1992}, note = {Reprinted in Avalanche Safety Course Manual (Canadian Avalanche Association, 1993-1996) and in Avalanche Instructor's Manual (National Ski Patrol, 1995). }, pages = {3-7}, institution = {Canadian Avalanche Association}, author = {Jamieson, Bruce and Colin Johnston} } @article { 194, title = {Snowpack characteristics associated with avalanche accidents. }, journal = {Canadian Geotechnical Journal }, volume = {29}, year = {1992}, pages = {862-866}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @proceedings { 198, title = {The width of unconfined slab avalanches based on field measurements of slab properties . }, year = {1991}, pages = {234-244}, institution = {Canadian Avalanche Association}, address = {Bigfork, Montana}, author = {Jamieson, J.B. and C.D. Johnston} } @article { 197, title = {The width of unconfined slab avalanches. }, volume = {10}, year = {1991}, pages = {3-6}, institution = {Canadian Avalanche Association}, author = {Jamieson, Bruce and Colin Johnston} } @article { 199, title = {In situ tensile tests of snowpack layers. }, journal = {Journal of Glaciology }, volume = {36}, year = {1990}, pages = {102-106}, institution = {Canadian Avalanche Association}, author = {Jamieson, J.B. and C.D. Johnston} } @proceedings { 200, title = {In situ tensile strength measurements of alpine snow. }, year = {1989}, pages = { 103-112}, institution = {Canadian Avalanche Association}, address = {Whistler, B.C.}, author = {Jamieson, J.B. and C.D. Johnston} } @phdthesis { 201, title = {In situ tensile strength of snow in relation to slab avalanches. }, year = {1988}, pages = {142}, school = {University of Calgary}, institution = {Canadian Avalanche Association}, type = {MSc}, address = {Calgary, Alberta, Canada}, author = {Jamieson, J. B.} }