Rock falls in the Mont Blanc Massif in 2007 and 2008

• Published in: Landslides
• Main Authors: Ravanel, Ludovic, Allignol, Françoise, Deline, Philip, Gruber, Stephan, Ravello, Mario
• Other Authors: Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Glaciology, Geomorphodynamics & Geochronology Group, Universität Zürich Zürich = University of Zurich (UZH)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: Rock falls . Permafrost . High alpine environments . Mountains . Mont Blanc Massif; permafrost
• Online Access: https://hal.science/halsde-00674973; https://doi.org/10.1007/s10346-010-0206-z

International audience Due to a lack of systematic observations, the intensity and volume of rock falls and rock avalanches in high mountain areas are still poorly known. Nevertheless, these phenomena could have burly consequences. To document present rock falls, a network of observers (guides, mountaineers, and hut wardens) was initiated in the Mont Blanc Massif in 2005 and became fully operational in 2007. This article presents data on the 66 rock falls (100 m3≤V≤50,000 m3) documented in 2007 (n=41) and 2008 (n= 25). Most of the starting zones are located in warm permafrost areas, which are most sensitive to warming, and only four rock falls are clearly out of permafrost area. Different elements support permafrost degradation as one of the main triggering factors of present rock falls in high mountain areas.