This video is about the first estimates of risk from rider triggered avalanches for various levels of avalanche danger. It assumes the skier does NOT use skilled route selection, i.e. the skier "center punches" the avalanche start zones. A presentation based on the paper: B. Jamieson, Schweizer, J., and Shea, C. 2009 Simple calculations of avalanche risk for backcountry skiing, International Snow Science Workshop. Davos, Switzerland. https://arc.lib.montana.edu/snow-science/objects/issw-2009-0336-0340.pdf

Using case studies, Bruce Jamieson, Thomas Exner and Brad White explain how solar warming can make natural and human-triggered dry slab avalanches more likely.

This video explains why the 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. #crackpropagation #ASARC #interpretation #snowpacktest

Hopefully, this presentation will spark discussion on how to classify avalanche size, especially for big avalanches. Based on a paper presented at the 2014 Geohazards 6 conference in Kingston, Ontario. For the paper behind this presentation, search for: large avalanche selkirk reflections #geohazards6 #avalanche #size #destructivepotential #selkirkmountains #size5 #classification

Includes avalanches in motion but no models and almost no math. Intended for anyone interested in avalanche science, early career avalanche practitioners, and pre-course viewing for students of avalanche planning/dynamics/engineering. Bruce Jamieson and Christian Jaedicke. Thanks to Peter Gauer and Chris Wilbur for helpful comments. August 2022.

In this (controversial?) 21 minute video, Bruce Jamieson, Karl Birkeland, Grant Statham and Scott Thumlert summarize some common perceptions about slab tension, then review the role of slab tension in the current understanding of dry slab avalanche release.

In February 2000, Crane Johnson and ASARC colleagues used geophones to measure the speed of a crack propagating in a weak snowpack layer.This measurement triggered theory, modeling and field studies into avalanche release. (This video is the first in a series to preserve narratives of turning points in avalanche research.) Crane Johnson, Greg Johnson, Karl Birkeland, Bruce Jamieson. CC BY-ND. #avalanche #slab #crackspeed #bending #wave #collapse #propagation #crackpropagation

Starting with the likelihood definition and terms in the Conceptual Model of Avalanche Hazard (Statham et al., 2018), Scott Thumlert, Grant Statham and Bruce Jamieson present some ideas for improving avalanche likelihood and how it can be communicated. Presented at the Virtual Snow Science Workshop, Fernie, Canada, October 2020. #avalanche #snow #likelihood #probability #frequency #referenceclass #conceptualmodel

A techy video for avalanche practitioners and recreationists interested in avalanche science. The video outlines the formation of faceted layers near melt-freeze crusts, the persistence of these layers as potential failure layers for slab avalanches and some ideas on anticipating the resulting slab avalanches. Bruce Jamieson and Scott Savage, May 2020. #persistentweaklayer #weaklayer #meltfreezecrust #faceting #facet #crust #avalanche #snow #slabavalanche

Weak snowpack layers formed by near surface faceting were under-recognized prior to Karl Birkeland's field studies and publications in 1998. This story from recognition of near surface faceting to forecasting and public communication is told by Karl Birkeland, Doug Chabot, Ed Adams, Mark Staples, Mike Cooperstein and Ethan Greene. #avalanche #slab #facet #persistent #weaklayer #forecasting #snow #research CC BY-ND

Chapter 1 (of 3) outlines the formation of surface hoar. Chapter 2 covers changes to buried surface hoar and propagation propensity. Chapter 3 is about choosing terrain and how pros track persistent weak layers. #surfacehoar #slabavalanche #avalanche #forecasting #persistentweaklayer #avalancheforecasting #simonhorton For more on the following topics briefly mentioned in the video, follow the links: - Rider triggering (including triggering from a thin area) and crack propagation in weak layers. https://vimeo.com//773056211 - Surface energy exchange and near surface faceting. https://vimeo.com/243958459 Simon Horton and Bruce Jamieson, uploaded 23 October 2023. CC BY-ND. For help with the video, we thank Greg Johnson, Marc Piché, Dave Gauthier, Karl Klassen, Doug Chabot, John Buffery, Bill Mark, Ryan Buhler, Steve Conger, Brad Stanton, Dan Miller, Ed Adams & past ASARC students and staff. Key references: 1. S. Horton and Jamieson, B. 2016. Modelling hazardous surface hoar layers throughout western Canada with a coupled weather and snow cover model. Cold Regions Science and Technology 128, 22-31. 2. B. Jamieson and Schweizer, J. 2000. Texture and strength changes of buried surface hoar layers with implications for dry snow-slab avalanche release. Journal of Glaciology 46(152), 151-160.

Chapter 2 of Some science behind surface hoar and its insidious avalanches - Changes to buried surface hoar and its propagation propensity. For more on the following topic briefly mentioned in the video, follow the link: - Rider triggering (including triggering from a thin area) and crack propagation in weak layers. https://vimeo.com//773056211 Simon Horton and Bruce Jamieson, 28 October 2023 #crack #surfacehoar #slabavalanche #avalanche #avalancheforecasting #metamorphism #crackpropagation For help with the video, we thank Greg Johnson, Marc Piché, Dave Gauthier, Karl Klassen, Doug Chabot, John Buffery, Bill Mark, Ryan Buhler, Steve Conger, Brad Stanton, Dan Miller, Ed Adams & past ASARC students and staff. Key references: 1. S. Horton and Jamieson, B. 2016. Modelling hazardous surface hoar layers throughout western Canada with a coupled weather and snow cover model. Cold Regions Science and Technology 128, 22-31. 2. B. Jamieson and Schweizer, J. 2000. Texture and strength changes of buried surface hoar layers with implications for dry snow-slab avalanche release. Journal of Glaciology 46(152), 151-160.