Videos for avalanche planners
The videos posted to this channel since ~2015 are by Bruce Jamieson (snowline.ca) and colleagues. Some of the earlier videos on this channel are links to videos made by Bruce Jamieson and ASARC colleagues (UCalgary.ca/asarc). The links to all these videos can be shared freely and the videos used for any purpose, including commercially, provided the content and authorship are not altered.
Videos for avalanche planners
How differences between snow avalanches and other slope hazards affect mapping and mitigation
Abstract: Snow avalanches differ from other slope hazards such as debris flows and landslides in ways that affect mapping and mitigation. Snow avalanches start as a result of failure in a bonded granular material in which the bonds are close to the melting point. Periods of instability are often limited to hours or days. In contrast to other slope hazards, explosives are effective triggers of unstable snow, thereby shortening periods of instability and allowing parts of ski areas or transportation corridors to be quickly re-opened. Where snow avalanche occurrences observations are available for a decade or more, this often results in better occurrence and runout records than for other slope hazards. For snow avalanches, hazard mapping thresholds based on a low annual probability (e.g. Pa ≤ 10-3) are especially uncertain and problematic for hazard mapping. A presentation video for GeoVirtual, September 2020. Bruce Jamieson, Dave Gauthier and Chris Wilbur. CC BY-ND
Has the snow climate changed in western Canadian mountains?
Climate change has been a focus for the avalanche world over the last few years, and our group has recently contributed two papers to the discussion, which we have summarised here. They both look at avalanches and how they have changed over the last 30 - 50 years. Before we get into those, let’s take a minute to explore why this is such a tricky topic, and why it is important to understand better. So why is it tricky? There are at least three reasons as to why it is hard to find a trend amongst the noise for avalanches: 1) It is not realistic to attribute any change in avalanche activity to any one single weather factor. We all know that avalanches depend on combinations of precipitation, wind, temperature etc. 2) Avalanche activity occurs on a weather system scale of days, rather than climate scale of decades. This is further complicated by atmospheric phenomena such as El Nino or PDO. 3) Third, avalanche-related data are often incomplete, inconsistent or spread across vast geographic regions. For example, in Canada, we can go back only about 50 years for reliable written records. Unfortunately the records are usually in populated areas where there has been human interference or involvement in the natural behaviour of avalanches through explosives (mountain passes) or compaction (ski hills). And why is it important to understand? Apart from the obvious concern we all have for the alpine environment, we also need to consider that avalanche risk assessment and mitigation techniques assume that avalanche occurrence is stationary, meaning it doesn’t change over time. We use return periods to design hazard maps, defense structures and industrial operations plans. Often these return periods are derived from historical data, which we assume won’t change into the future. Studies such as these will help us decide if changes in explosive control may be required or if the boundaries of hazard zones should be adjusted.
How do snow avalanches differ from other slope hazards?
This video identifies some key differences between snow avalanches and other slope hazards. Hopefully, the video (and the book on Planning Methods for Snow Avalanche Risk) will help those who plan for various slope hazards better understand snow avalanche hazards.