A probabilistic method to assess rockfall risk on mountaineering trail: the Couloir du Goûter study case

Rockfall represents one of the most crucial hazards in mountain environment. Global warming and climate change increase the frequency and the altitude at which events occur, increasing the number of fatal accidents or injuries on mountaineering trail paths. To predispose effective actions, a quantification of the risk in terms of annual probability of death for hikers becomes an urgent issue. A quantitative risk assessment method based on event tree analysis, tailored for the specific case, is proposed and applied to the study case of the Couloir du Gouter, one of the most critical points of the ascent to Mont Blanc.