On the relation between avalanche occurrence and avalanche danger level
In many countries with seasonally snow-covered mountain ranges warnings are issued to alert the public about imminent avalanche danger, mostly employing an ordinal, five-level danger scale. However, as avalanche danger cannot be measured, the characterization of avalanche danger remains qualitative....
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ftunivzuerich:oai:www.zora.uzh.ch:186121 2024-09-15T18:39:00+00:00 On the relation between avalanche occurrence and avalanche danger level Schweizer, Jürg Mitterer, Christoph Techel, Frank Stoffel, Andreas Reuter, Benjamin 2020-03-02 application/pdf https://www.zora.uzh.ch/id/eprint/186121/ https://www.zora.uzh.ch/id/eprint/186121/1/schweizer_etal_2020_avalanches_davos_danger_level.pdf https://doi.org/10.5167/uzh-186121 https://doi.org/10.5194/tc-14-737-2020 eng eng Copernicus Publications https://www.zora.uzh.ch/id/eprint/186121/1/schweizer_etal_2020_avalanches_davos_danger_level.pdf doi:10.5167/uzh-186121 doi:10.5194/tc-14-737-2020 urn:issn:1994-0416 info:eu-repo/semantics/openAccess Creative Commons: Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/ Schweizer, Jürg; Mitterer, Christoph; Techel, Frank; Stoffel, Andreas; Reuter, Benjamin (2020). On the relation between avalanche occurrence and avalanche danger level. The Cryosphere, 14(2):737-750. Institute of Geography 910 Geography & travel Earth-Surface Processes Water Science and Technology Journal Article PeerReviewed info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2020 ftunivzuerich https://doi.org/10.5167/uzh-18612110.5194/tc-14-737-2020 2024-08-28T00:37:26Z In many countries with seasonally snow-covered mountain ranges warnings are issued to alert the public about imminent avalanche danger, mostly employing an ordinal, five-level danger scale. However, as avalanche danger cannot be measured, the characterization of avalanche danger remains qualitative. The probability of avalanche occurrence in combination with the expected avalanche type and size decide on the degree of danger in a given forecast region (≳100 km2). To describe avalanche occurrence probability, the snowpack stability and its spatial distribution need to be assessed. To quantify the relation between avalanche occurrence and avalanche danger level, we analyzed a large data set of visually observed avalanches (13 918 in total) from the region of Davos (eastern Swiss Alps, ∼300 km2), all with mapped outlines, and we compared the avalanche activity to the forecast danger level on the day of occurrence (3533 danger ratings). The number of avalanches per day strongly increased with increasing danger level, confirming that not only the release probability but also the frequency of locations with a weakness in the snowpack where avalanches may initiate from increase within a region. Avalanche size did not generally increase with increasing avalanche danger level, suggesting that avalanche size may be of secondary importance compared to snowpack stability and its distribution when assessing the danger level. Moreover, the frequency of wet-snow avalanches was found to be higher than the frequency of dry-snow avalanches for a given day and danger level; also, wet-snow avalanches tended to be larger. This finding may indicate that the danger scale is not used consistently with regard to avalanche type. Even though observed avalanche occurrence and avalanche danger level are subject to uncertainties, our findings on the characteristics of avalanche activity suggest reworking the definitions of the European avalanche danger scale. The description of the danger levels can be improved, in particular by quantifying ... Article in Journal/Newspaper The Cryosphere University of Zurich (UZH): ZORA (Zurich Open Repository and Archive |
institution |
Open Polar |
collection |
University of Zurich (UZH): ZORA (Zurich Open Repository and Archive |
op_collection_id |
ftunivzuerich |
language |
English |
topic |
Institute of Geography 910 Geography & travel Earth-Surface Processes Water Science and Technology |
spellingShingle |
Institute of Geography 910 Geography & travel Earth-Surface Processes Water Science and Technology Schweizer, Jürg Mitterer, Christoph Techel, Frank Stoffel, Andreas Reuter, Benjamin On the relation between avalanche occurrence and avalanche danger level |
topic_facet |
Institute of Geography 910 Geography & travel Earth-Surface Processes Water Science and Technology |
description |
In many countries with seasonally snow-covered mountain ranges warnings are issued to alert the public about imminent avalanche danger, mostly employing an ordinal, five-level danger scale. However, as avalanche danger cannot be measured, the characterization of avalanche danger remains qualitative. The probability of avalanche occurrence in combination with the expected avalanche type and size decide on the degree of danger in a given forecast region (≳100 km2). To describe avalanche occurrence probability, the snowpack stability and its spatial distribution need to be assessed. To quantify the relation between avalanche occurrence and avalanche danger level, we analyzed a large data set of visually observed avalanches (13 918 in total) from the region of Davos (eastern Swiss Alps, ∼300 km2), all with mapped outlines, and we compared the avalanche activity to the forecast danger level on the day of occurrence (3533 danger ratings). The number of avalanches per day strongly increased with increasing danger level, confirming that not only the release probability but also the frequency of locations with a weakness in the snowpack where avalanches may initiate from increase within a region. Avalanche size did not generally increase with increasing avalanche danger level, suggesting that avalanche size may be of secondary importance compared to snowpack stability and its distribution when assessing the danger level. Moreover, the frequency of wet-snow avalanches was found to be higher than the frequency of dry-snow avalanches for a given day and danger level; also, wet-snow avalanches tended to be larger. This finding may indicate that the danger scale is not used consistently with regard to avalanche type. Even though observed avalanche occurrence and avalanche danger level are subject to uncertainties, our findings on the characteristics of avalanche activity suggest reworking the definitions of the European avalanche danger scale. The description of the danger levels can be improved, in particular by quantifying ... |
format |
Article in Journal/Newspaper |
author |
Schweizer, Jürg Mitterer, Christoph Techel, Frank Stoffel, Andreas Reuter, Benjamin |
author_facet |
Schweizer, Jürg Mitterer, Christoph Techel, Frank Stoffel, Andreas Reuter, Benjamin |
author_sort |
Schweizer, Jürg |
title |
On the relation between avalanche occurrence and avalanche danger level |
title_short |
On the relation between avalanche occurrence and avalanche danger level |
title_full |
On the relation between avalanche occurrence and avalanche danger level |
title_fullStr |
On the relation between avalanche occurrence and avalanche danger level |
title_full_unstemmed |
On the relation between avalanche occurrence and avalanche danger level |
title_sort |
on the relation between avalanche occurrence and avalanche danger level |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://www.zora.uzh.ch/id/eprint/186121/ https://www.zora.uzh.ch/id/eprint/186121/1/schweizer_etal_2020_avalanches_davos_danger_level.pdf https://doi.org/10.5167/uzh-186121 https://doi.org/10.5194/tc-14-737-2020 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
Schweizer, Jürg; Mitterer, Christoph; Techel, Frank; Stoffel, Andreas; Reuter, Benjamin (2020). On the relation between avalanche occurrence and avalanche danger level. The Cryosphere, 14(2):737-750. |
op_relation |
https://www.zora.uzh.ch/id/eprint/186121/1/schweizer_etal_2020_avalanches_davos_danger_level.pdf doi:10.5167/uzh-186121 doi:10.5194/tc-14-737-2020 urn:issn:1994-0416 |
op_rights |
info:eu-repo/semantics/openAccess Creative Commons: Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.5167/uzh-18612110.5194/tc-14-737-2020 |
_version_ |
1810483394858975232 |