The project will be implemented in the Southern Alps, highly exposed to landslide and debris-flow hazards. This physical setting offers the advantage of being already covered by high-quality mapping products related to
- 1) debris-flow susceptibility and/or landslide occurrence,
- 2) and to distributed real-time rainfall radar data.
A nested-scale approach will be undertaken, with a regional scale including several alpine valleys in the Alpes-Maritimes, for assessing debris-flow and landslide threshold triggers, and a local scale including several municipalities for which implementation of multi-hazard EWSs tailored to the needs and preparedness of local authorities and populations will be developed.
The Upper Var and Vésubie valleys are foreseen for the regional scale approach. This geographic setting offers a great diversity of geological conditions, combined with strong relief gradients. This region is characterized by climatic gradients, with extreme rainfall regimes of different meteorological origins: Mediterranean episodes in autumn (e.g. Alex Storm in October 2020), eastern frontal storms during spring, and convective storms during spring and summer. The recent history of this region is full of damaging debris-flow and landslide events (Fig. 1), the most recent ones being those triggered during Alex storm along numerous headwaters of the Vésubie, Roya end Tinée valleys (Fig. 2). covered by two X-band polarimetric weather radars recently deployed to improve the Aramis network of Météo France (Fig. 2). These new radars provide a real time monitoring of rainfall amount for different periods, at a spatial resolution of 500 m and a time resolution of 5 min.
At the local scale, the following municipalities are foreseen: Crots, and municipalities within the Vesubie valley (Saint-Martin Vésubie…)
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