Here you can find videos and information about our seminars and research projects.
There are two stages to fracture a weak layer under a skier, snowmobiler or other load: starting a fracture under the dynamic load, and - sometimes - sustained propagation away from the load.
To read the paper behind this video, search for: asarc yellow flags To read McCammon and Schweizer's paper on Lemons, search for: Mcammon lemons
The two papers behind this short video are available at http://www.sciencedirect.com/science/article/pii/S0165232X15002505 and http://www.tandfonline.com/doi/abs/10.1080/15732479.2015.1020495
by Shane Haladuick
This is part of a presentation given at the 2014 International Snow Science Workshop, in Banff AB. Please see the corresponding paper for more details: ucalgary.ca/asarc/Issw2014/RsoHaladuick
by Michael Schirmer
by Shane Haladuick
by Michael Schirmer
by Mike Conlan
You can skip ahead to particular tests, but note the summary and limitations at the end of the video.
by Shane Haladuick
For the ISSW 2013 paper on this topic, click http://www.ucalgary.ca/asarc/Issw2013/SnowpackTestsLocalDanger_Haladuick
by Simon Horton
by Simon Horton
by Scott Thumlert
by Alex Sinickas
by Thomas Exner
by Bruce Jamieson & Alan Jones
This video is based on a paper posted at http://www.ucalgary.ca/asarc/issw2013/Iso31k_Jamieson
An ISSW 2012 presentation by Simon Horton.
An ISSW 2012 presentation by Scott Thumlert.
From an ISSW 2012 paper with Alan Jones.
Some calculations of risk for skiing at various levels of avalanche danger - from an ISSW 2009 paper.
Mike Conlan talks about his research to improve the forecasting of deep slab avalanches..
Simon Horton talks about his research to predict the size of surface hoar hoar crystals that form on different aspects. He also presents his ideas for estimating the persistence of buried layers based on crystal size at burial and other factors.
Ryan Buhler summarizes results from his last two winters of studying the changes in melt-freeze crusts after they are buried.
Alex Sinickas outlines the ideas and methods for her research into estimating extreme avalanche runout for land-use planning.
Sascha Bellaire talks about simulating the snowpack with a computer model that inputs data from the GEM15 weather forecasts. By coupling the weather and snowpack models, the snowpack can be predicted anywhere. To see if or how well it works, watch the video.
Surface hoar is quite particular. A number of different factors determine what aspects it grows on, and on what aspects it will grow bigger. This video shows a small area (~1 m on a side) with small rolls of snow that have very large surface hoar on only one side. A thermal image overlying the visual image gives us insight into why a small aspect difference makes a big difference in surface hoar crystals.
Thermal images of freshly exposed pit walls, about hourly, show the snow at and near the surface cooling rapidly when the sky cleared. When the sky became cloudy, the snow surface warmed by the greenhouse effect. These radiation effects are usually the dominant short term (24 h) effects except when rather strong wind warms or cools the surface. You can download the poster shown in the video from http://webapps2.ucalgary.ca/~asarc/files/ShallowSnowPoster_Shea_Jan2012.png.
About twice per week at a shallow snowpack site in the Canadian Rockies during the winter of 2011, Cora Shea took thermal images of the pit wall and micro-photographs of the crystals in the crust and adjacent layers. It appears the less permeable crust contributes to faceting below the crust. You can download the poster shown in the video from http://webapps2.ucalgary.ca/~asarc/files/ShallowSnowPoster_Shea_Jan2012.png.
During visits to a shallow snowpack in the Rockies during the winter of 2010-11, Cora Shea took thermal images of the freshly exposed pit wall, and micro-photographs of the crystals in and adjacent to the crust. Some days the crust was warmer than adjacent layers - suggesting net deposition of water vapour (faceting). Some days the crust was colder than adjacent layers. You can download the poster shown in the video from http://webapps2.ucalgary.ca/~asarc/files/ShallowSnowPoster_Shea_Jan2012.png.
Scott Thumlert explains stress bulbs in the snowpack caused by skiers and snowmobiles moving over the snowpack, and summarizes the results from the the first winter of controlled measurements, including the strong effects of stiff surface layers as well as ski/sled penetration into the snowpack.
Dave Gauthier explains why the PST was developed, shows two demonstrations of the propagation saw test, explains the usual interpretation of test results, and shows how it performed next to real avalanches and whumpfs over four winters.
This video summarizes some of Alec van Herwijnen's research on Fracture character. On skier-triggered slopes, two types of fractures - Sudden Planar and Sudden Collapse - were more common than other types of fractures.
Katherine Johnston explains her MSc research on statistical estimation of extreme avalanches for the Columbia Mountains and for the Fernie Area.
SWarm is a free spreadsheet that estimates daytime warming 10 cm below the surface over idealized terrain. You can select the date, expected cloud cover, and days since snowfall to see how these factors can influence the daytime snowpack warming on slopes of various aspects and steepness.
GSWarm is a website that displays the estimated snowpack warming for selected areas in western Canada such as Rogers Pass and Crowsnest Pass. You can select the date, expected cloud cover, and days since snowfall to see how these factors can influence the snowpack warming down 10 cm.
ASARC is using thermal photography to study processes at the surface of and within the snowpack.
We can often see individual snow layers of interest, including facets, surface hoar, and the temperature stress that new snow is putting on the old surface.
Photos such as the one of facet chains above show how temperature directly drives metamorphism within the snowpack.
Avalanche research doesn't always happen in the winter! ASARC is working to develop new statistical runout models for the Columbia mountains and the Lizard Range in BC.
These runout models will give a better, more local, prediction of extreme avalanche events in areas that do not follow the more general models well.
Deep persistent slab avalanches are extreme events that are very difficult to predict.
ASARC is working to visit these deep avalanche event sites and perform tests that will help us understand common trends and patterns between them.
The snowpack is different everywhere. This is the theme behind the term 'spatial variability'. ASARC, in conjunction with previous work done at the SLF in Switzerland, is working to better understand what tests can help us understand stability despite the presence of spatial variability.
The RSO project combines observations from researchers across the three climate regimes (maritime, transitional, continental) to find out which observations matter the most for which regimes and avalanche types. These observations are designed to be fast and simple, for use on a day of recreational backcountry skiing or snowmobiling.
Here is a short video of our most requested presentation from the last decade. There are a couple of relevant papers on our publication page. Search for Fracture Character or Pops.
We are measuring the dynamic stress in the snowpack caused by skiers, snowmobiles, etc. This 11-second video shows a person falling directly above the stress sensors. Scott Thumlert is running the datalogger and stress sensors, which are hard to see in this video.
As part of a research project on triggering of dry slab avalanches, MSc student Scott Thumlert has placed pressure sensors in the snowpack. A datalogger records the dynamic stress due to the snowmobile travelling over the pressure sensors.
Sascha Bellaire rides a wild rutschblock. .
Testing a surface hoar layer under a soft slab. Since the saw cut is less than half the column length and the fracture shoots to the end of the column, the test indicates fracture propagation is likely (where snowpack conditions are similar).
Dave Gauthier demonstrates a propagatiion saw test on level ground. Chocolate powder has been blown onto the wall of the column to make the fracture (collapse) more visible.