Item: FORECASTING STORM-SNOW AVALANCHES USING A COMBINED SHEAR AND ANTICRACK INSTABILITY MATRIX
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Title: FORECASTING STORM-SNOW AVALANCHES USING A COMBINED SHEAR AND ANTICRACK INSTABILITY MATRIX
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Benjamin H. Silberman [ University of Utah, Salt Lake City, UT, USA ]
- Eric R. Pardyjak [ University of Utah, Salt Lake City, UT, USA ]
- Dhiraj K. Singh [ University of Utah, Salt Lake City, UT, USA ]
- Jim Steenburgh [ University of Utah, Salt Lake City, UT, USA ]
- Steven Clark [ Utah Department of Transportation ]
- Travis Morrison [ University of Utah, Salt Lake City, UT, USA ] [ Utah Avalanche Center ]
- Jack Eskeland [ Utah Avalanche Center ]
Date: 2026-09-28
Abstract: Forecasting storm-snow avalanches remain challenging due to limited access to the mechanical properties of snow during active snowfall and the lack of a unified framework that captures multiple failure modes. This work presents a physics-based avalanche decision-support system that combines a shear-strength stability index (SIsh) with an anticrack stability index (SIant) to generate a more comprehensive stability matrix. This stability matrix is designed to provide a practical tool for identifying unstable storm-snow conditions and distinguishing between shear-driven and anticrack-driven failure mechanisms. The proposed framework leverages real-time measurements from a Differential Emissivity Imaging Disdrometer (DEID) to capture snow microstructure and density, which are used to drive both stability indices. These indices are combined into a two-dimensional decision matrix that enables intuitive interpretation of snowpack stability for avalanche practitioners. To extend beyond nowcasting, the stability matrix is coupled with output from the High-Resolution Rapid Refresh (HRRR) weather model, allowing forecasts of storm-snow instability up to 48 hours in advance. Model performance will be evaluated using georadar detections, infrasound records, and manual avalanche observations within Little Cottonwood Canyon, Utah. These datasets will be combined with additional storm-specific information such as precipitation intensity and detailed Utah Department of Transportation (UDOT) mitigation records, to inform how these avalanches failed, and on what layer of snow. Preliminary results of model validation with georadar and infrasound avalanche detection systems will be presented. Additional results will include comparisons with avalanche observations submitted to the Utah Avalanche Center. These model comparisons will be visualized through clear, informative graphics for easy interpretation by snow operationalists.
Object ID: ISSW2026_O4.3.pdf
DOI: https://doi.org/10.15788/1790098590
Language of Article: English
Presenter(s): Benjamin Silberman
Keywords: avalanche forecasting, storm-snow, anticrack, shear strength, stability index, densification
Page Number(s): 964 - 970
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