A fuzzy explanatory model to assess the mode of vigilance in avalanche terrain

Mountain sports are exposed to the risk of avalanches. In France, an average of 20 people per year (average over the last 5 winters) dies in avalanches among ski tourers, off-piste skiers and mountaineers. Against this background, the aim of this research is to contribute to improving decision-making in the face of avalanche risk, in order to reduce as far as possible the number of accidents and incidents that occur each year. To this end, our approach is based on expert knowledge expressed by a set of fuzzy rules that combine different physical variables to build an ordinal fuzzy scale of vigilance (“Relaxed”, “Suspicious”, “Alert”, “Gamble”). The level of vigilance to be applied locally, along a mountain ski route, also needs to be explained in a way that is close to expert reasoning.