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Abstract

Several recent studies have examined avalanche forecast users’ ability to understand the provided hazard information, but they have so far not evaluated how users combine the information with additional avalanche knowledge to assess the severity of the conditions on individual slopes, which is a critical skill for the effective application of the forecast information during trip planning. We conducted an online experiment with members of the Euregio and Swiss avalanche forecast research panels where participants were presented with a series of hypothetical avalanche forecasts and asked to rank four slopes according to their avalanche risk. Each slope was characterized by a different combination of aspect, elevation, and slope steepness, which was described using the standard qualitative terms defined by the European Avalanche Warning Services. Our survey also included several questions examining participants’ understanding of the qualitative steepness terms. Our revealed that only 16% of the sample provided the “Graphic Reduction Method” solution to the slope tanking exercise, while 55% used a sequential approach where they first split the slopes according to the provided danger rating and then ranked them according to steepness. The responses to the questions on the steepness terms showed that approximately half of our participants believe that ‘extreme terrain’ starts at inclines that are steeper than the 40° threshold defined by EAWS. This means that they potentially underestimate the severity of the terrain described in forecasts. We derive several management implications for avalanche warning services from our results.