Item: When to dig? thoughts on estimating slope stability
Title: When to dig? thoughts on estimating slope stability
Proceedings: 2010 International Snow Science Workshop
Authors: Sascha Bellaire1*, Bruce Jamieson1, 2, Jürg Schweizer3 1 Dept. of Civil Engineering, University of Calgary, AB, Canada 2 Dept. of Geoscience, University of Calgary, AB, Canada 3 WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Abstract: Information about the snow cover stability is crucial for avalanche forecasting and for winter backcountry recreation. For a reliable estimation of snow cover stability at all levels of stability and over terrain many stability tests would be required. These tests are time consuming and therefore not practical for backcountry recreationists. Sampling strategy becomes important if spatial variability is considered as a key component of avalanche release. A recently proposed sampling strategy for slope stability estimation allows one to estimate the slope stability with a maximum of four compression tests. However, since backcountry recreationists as well as avalanche professionals during recreation rarely perform stability tests, we wade into this important and controversial question: to dig or not to dig? We review and discuss sampling strategies and methods from the perspective of experienced and less experienced recreationists. Factors were identified which increase or decrease the value of snow cover observations – which require digging – for recreationists in order to estimate the snow cover stability. These factors include experience level, local observations – which do not require digging – from previous days and the current day, ability to interpret observations over terrain and across spatial scales as well as cumulative knowledge of the snowpack. In conclusion, the question is not "To dig or not to dig?", but "When to dig?" – the latter question we try to answer.
Keywords: slope stability, avalanche forecasting, winter backcountry recreation