Item: Avalanche Forecast Verification and Occurrence in Scotland, 2007–2025
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Title: Avalanche Forecast Verification and Occurrence in Scotland, 2007–2025
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Ian N. Durbach [ University of St Andrews, St Andrews, UK ]
- Blair Fyffe [ Scottish Avalanche Information Service, UK ]
- Brian Morrison [ Scottish Avalanche Information Service, UK ]
- Mark Diggins [ Scottish Avalanche Information Service, UK ]
- Philip A. Ebert [ University of Salzburg, Salzburg, Austria ]
Date: 2026-09-28
Abstract: The Scottish Avalanche Information Service (SAIS) has issued daily avalanche forecasts across Scotland since 1988. In 2016, the service adopted the European Avalanche Danger Scale and structured, matrix-based forecasting guidance. We analysed 11,516 forecasts produced by 63 forecasters across six regions during the 2007/08–2024/25 seasons, together with 3,193 reported avalanches, to describe changes associated with this transition and provide the first comprehensive account of avalanche forecasting and occurrence in Scotland. Exact agreement between forecast and target-day observed hazard rose from 61.2% to 80.8% after the transition, and the multcategory Peirce skill score from 0.535 to 0.665, with scores increased for 11 of 12 adequately sampled forecasters. Calibration between forecast hazard and reported avalanche occurrence also improved. Scores tended to be slightly higher when forecasters verified their own forecasts. Forecast hazard was not elevated at weekends, but reported avalanches were more frequent, which may reflect increased observation.. The analysis is descriptive rather than causal, but provides a quantitative baseline for future verification and practical recommendations for strengthening the verification process.
Object ID: ISSW2026_P2.14.pdf
DOI: https://doi.org/10.15788/1790098911
Language of Article: English
Presenter(s): Mark Diggins
Keywords: avalanche forecasting, forecast verification, danger level, avalanche occurrence, Scotland
Page Number(s): 492 - 500
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