Feasibility of Seismic Monitoring to Identify Avalanche Activity: Snoqualmie Pass, Wa

Kathryn Johnston
June 2013

Abstract

Avalanches across the Interstate-90 corridor over Snoqualmie Pass, in Washington State, are a concern for winter travelers and backcountry recreation. The temporary closure of the interstate for avalanche mitigation work also affects commerce by delaying transportation of merchandise. The study of seismic signals associated with snow avalanches could allow for greater understanding of avalanche properties, while remote sensing of avalanche activity could help established avalanche control programs and regional avalanche centers with forecasting and mitigation efforts. Two seismic stations were installed near the Alpental ski area on Snoqualmie Pass and recorded seismic activity throughout the winters of 2009-2010 and 2010-2011. During the winter of 2010-2011, two avalanches were successfully recorded, one artificially released with explosives and one naturally during a rain on snow event. These results show that it is possible to record avalanche activity over the traffic noise of the interstate and that avalanche activity can be distinguished from other seismic sources. Similarities in the seismic signals with previous research show distinct characteristics associated with avalanches, however, no further conclusions on the seismic characteristics unique to this avalanche path can be made with such a small sample size; more research is necessary.

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