A 100-year extreme snow-avalanche record based on tree-ring research in upper Bodalen, inner Nordfjord, western Norway

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TitreA 100-year extreme snow-avalanche record based on tree-ring research in upper Bodalen, inner Nordfjord, western Norway
Type de publicationJournal Article
Year of Publication2014
AuteursDecaulne A, Eggertsson O, Laute K, Beylich AA
JournalGEOMORPHOLOGY
Volume218
Pagination3-15
Date PublishedAUG 1
Type of ArticleArticle
ISSN0169-555X
Mots-clésExtreme snow avalanches, Outlet glacier source-area, Tree-ring record, Upper Bodalen valley, Western Norway, Wintry weather conditions
Résumé

This paper analyses with the help of tree-ring studies the recurrence of extreme snow avalanches in a path situated in the upper Bodalen valley and originating from an outlet glacier of the Jostedalsbreen ice cap. By analysing tree-ring patterns of 91 trees, four extreme snow-avalanche events, extending over the entire valley floor and up to a distance of 800 m from the foot of the slope, are clearly highlighted during the 20th century and at the beginning of the 21st century. Return periods of 15 to 20 years for the most extreme events are extracted from the analyses, and recurrence intervals of 10 to 15 years for avalanches presenting distinct deposition lobes uphill of the distal torrent Results obtained by tree-ring analyses are successfully compared with available documents at different spatial and temporal scales. Rock-face snow-avalanche occurrences in the area, of small to medium size, are associated with heavy wintry precipitation combined with strong winds. However this normal situation is not valid for extreme snow avalanches crossing the path investigated in the paper, which result from the outlet glacier located in the starting zone; this glacier commands spatial and inter-annual variations of snow accumulation in the departure zone. (C) 2014 Elsevier B.V. All rights reserved.

DOI10.1016/j.geomorph.2013.12.036