Global warming decreases the snow cover of the peaks of the Sancy massif but also affects the process and timing of snowmelt. When less accumulated on the ground, the snow melts earlier in the year but also more slowly than during a massive summer melt. This early and slow melting favors the evaporation of water, to the detriment of the high water flows normally generated by the late melting of a larger layer of snow which then deeper feed the waterways and the groundwater.