Item: Applications of risk matrices for avalanche forecasting and education
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Title: Applications of risk matrices for avalanche forecasting and education
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Bruce Tremper [ Retired Director, Utah Avalanche Center, USA ]
Date: 2018-10-07
Abstract: Risk matrices are widely used in most fields that deal with risk. These are also called probability/consequence diagrams or FN diagrams (frequency/number). They have been only recently adopted into the fields of avalanche forecasting, avalanche education and backcountry travel. For the past few years most avalanche forecasting operations, public avalanche forecasts and avalanche educators in North America have been using the diagram we created in A Conceptual Model of Avalanche Hazard (Statham et al, 2010, 2018), which plots likelihood of an avalanche on the vertical axis and avalanche size on the horizontal axis as a way to conceptualize and visualize probability and consequence of avalanche hazard as well as variability and uncertainty. We use this diagram to plot where various avalanche problem types (avalanche characters) exist on the diagram. We can also use the diagram to plot hazard from a snow profile with the results of stability tests on the vertical axis and the mass of snow above the weak layer on the horizontal axis. An important use of risk matrices is to plot the danger of the snowpack versus the danger of the terrain, such as the Avaluator 2.0 (Canadian Avalanche Centre, 2010). I use a similar diagram in my publications and classes to conceptualize appropriate specific terrain choices based on given avalanche danger ratings. In addition, in the most recent editions of my avalanche books, (Avalanche Essentials, 2013; Staying Alive in Avalanche Terrain, 3rd Edition, 2018) I also use various risk matrices to teach students how to judge the danger of specific terrain features by plotting steepness on the vertical axis (the closer to 39 degrees, the more likely an avalanche will occur) and terrain consequences on the horizontal axis (terrain traps, trees, cliffs or crevasses). Finally, risk matrices have also been used to combine all the various factors that contribute to probability of a mishap (avalanche hazard, steepness, human factors, etc.) versus all the various factors that contribute to the consequence of a mishap (terrain consequences, rescue gear, rescue difficulties, medical and transportation issues, etc.). Jim Conway (2018) adapted a diagram from similar ones used by the U.S. Marine Corps specifically for use in avalanche guiding operations, as well as backcountry and rescue applications. This paper is an overview of the many graphical applications of risk matrices for avalanche forecasting, avalanche education and backcountry travel.
Object ID: ISSW2018_O17.7.pdf
Language of Article: English
Presenter(s):
Keywords: Risk Matrix, Risk, Hazard, Probability, Consequence
Page Number(s): 1517-1522
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