Item: BRINGING THE EUROPEAN AVALANCHE DANGER SCALE TO THE 21ST CENTURY
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Title: BRINGING THE EUROPEAN AVALANCHE DANGER SCALE TO THE 21ST CENTURY
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Dr. Karsten Müller [ Norwegian Water Resources and Energy Directorate ]
- Dr. Frank Techel [ WSL Institute for Snow and Avalanche Research SLF ]
- Dr. Christoph Mitterer [ Avalanche Warning Service Tyrol, Innsbruck, Austria ]
- Dr. Stefano Sofia [ AINEVA ]
- Petter Palmgren [ The Avalanche Forecast Service at Swedish EPA ]
- Nicolas Roux [ Météo France ]
- Guillem M. Bellido [ Andorran Weather and Avalanche Service ]
- Lorenzo Bertranda [ Meteomont Carabinieri ]
- Giacomo Villa [ Alpsolut, Livigno, Italy ]
Date: 2024-09-23
Abstract: The European Avalanche Danger Scale (EADS) is the governing document for public avalanche warning services in Europe. It has been the common ground to assess and communicate avalanche danger, with literally no changes since its introduction in 1993. However, since then, more concepts and tools have been added to standardize the production and communication of public avalanche warnings. The most prominent are the introduction of typical avalanche problems and the European Avalanche Warning Service (EAWS) Matrix, revised definitions of key terms used during the forecasting process, and a workflow tying all these elements together. However, these developments have led to differences between the terminology used in the EADS and these newer concepts. Therefore, an updated danger scale is needed, which integrates these developments, and which focuses on communicating avalanche danger to the public. Thus, language should be simple and clear while unambiguously connected to the technical definitions. Moreover, as the danger scale is the standard used by all avalanche warning services in Europe, it needs to work well in many languages. As a first step working towards a new danger scale, we analyzed data on how the governing factors of frequency of snowpack stability and avalanche size are used in connection to the avalanche danger levels in an operational forecasting context. From these data, obtained from 15 warning services during the forecasting season 2022/2023, we extracted typical descriptions for the danger levels. It showed that these align well with the EADS at the higher danger levels. However, it also indicates that forecaster tend to emphasize instability over stability at lower danger levels. We present a brief danger scale based on usage data and discuss choices and challenges that must be tackled to bring the EADS up to date.
Object ID: ISSW2024_O1.12.pdf
Language of Article: English
Presenter(s): Karsten Müller
Keywords: avalanche danger scale, public avalanche forecasting
Page Number(s): 70 - 76
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