Ravanel L. auteur aut IRD Mourey J. auteur aut IRD Tamian L. auteur aut IRD Ibanez S. auteur aut IRD Hantz D. auteur aut IRD Lacroix Pascal auteur aut IRD Duvillard P. A. auteur aut IRD text journalArticle fre text/pdf born digital access Mountaineering is a sport highly dependent on the conditions of the physical environments in which it takes place. As a result, mountaineers have to deal with major glacial and periglacial hazards, such as those affecting the two main routes used to climb Mont Blanc (4808 m a.s.l.; Western European Alps): rockfalls in the Grand Couloir du Gouter on the Voie Royale and serac falls on the NNW slope of Mont Blanc du Tacul on the Trois Monts route. Hazards in these two sectors and the number of climbers were measured using a multi-sensor system and automatic photographic acquisition, respectively. On the first site, which has a very high accident rate with an average of 3.7 deaths per year, 17,768 passages were recorded during the summer of 2019 and 2,648 seismic signals were classified as rockfalls affecting the Grand Couloir. The average risk of death associated with these rockfalls, the frequency of which depends on temperatures and the presence of liquid water in the ground, is estimated at 1.7 x 10-4. At Tacul, where an average of 0.6 deaths occur each year, 6,770 passages were recorded during the summer of 2017, as well as 31 serac falls unrelated to temperatures. The risk of death is 8.3 x 10-5. The risk is also quantified for each track made on the glacier. The results obtained makes it possible to specify the risks experienced by climbers and to promote risk reduction strategies. specialized Mountaineering serac fall rockfall risks Mont Blanc FRANCE ALPES 021 064 111 2 11765 [19 p.] 2023 0035-1121 https://www.documentation.ird.fr/hor/fdi:010088799 10.4000/rga.11728 0035-1121 [F B010088799] https://www.documentation.ird.fr/hor/fdi:010088799 https://www.documentation.ird.fr/intranet/publi/2024-01/010088799.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2024-01-12 2024-01-12 fdi:010088799 fre