Alpine snowpack builds normally, drains early

// L'hypothèse

Winter accumulation reaches or exceeds the 1991-2020 norm, but melt-out advances far enough that the snowpack no longer bridges the gap to the summer rains. The stock is not the variable; the residence time is.

5 countries · alpine and pyrenean catchments · irrigation and hydropower

// Impact modélisé

The 2026 season is the reference case. The snowpack measured about 3.50 m at 2 500 m in the northern Alps and Pyrenees on 2 April, a normal-to-good year by depth. By 1 June the snow water equivalent was locally more than 75% below normal, and the Col de Porte site was bare from 20 April. A record stock drained in roughly eight weeks. Downstream, the same signature appears at three depths — soil, snow, groundwater — after a winter of major floods. Alpine and Pyrenean catchments enter the irrigation season with the buffer already spent, and the shortfall lands on groundwater that is itself thinly monitored in exactly those departments.

La probabilité et la gravité sont des estimations internes sur la méthodologie v3.2. Données DÉMO, non destinées à la citation.