Analysis of the spatio-temporal fluctuations of avalanche numbers in the Northern Alps using the French Permanent Avalanche Survey (EPA) database

Abstract

Avalanche activity is surveyed in France by the National Forest Office and the Cemagref. The characteristics of all events occurring on certain sites are registered. The usual valorisation of this data is local predetermination. The database has also some interest from the phenomenological point of view thanks to its standardised protocol and to the length of the data series. As an illustration, this article analyses the fluctuations of avalanche numbers in the northern Alps over the last 60 winters. The spatio temporal structure that is highlighted can be linked to the geophysical characteristics of the different mountain massifs and to the large scale climatic variations. On the other hand, the obtained avalanche frequencies can be used in an operational context for evaluating return periods.