Alps Are Losing Snow

Seasonal snowpack is a key component of the mountain cryosphere, acting as a vital natural reservoir that regulates runoff downstream in snowfed basins. In mid- and low-elevation mountain regions such as the European Alps, snow processes, such as accumulation and ablation, are highly sensitive to climate change, having direct implications for hydrological forecasting and water availability.

This study provides the first comprehensive long-term (1991-2021) analysis of snow water equivalent changes in the Po River District, Italy, one of Europe’s second most climate sensitive regions. Our findings show stark elevation-dependent changes in snow water storage and duration with profound and immediate implications for water security and climate adaptation.

Using a high-resolution (500m, daily) dataset from 1991-2021 (Dall'Amico et al., 2025), we observed two primary findings: First, we observed a profound loss of snow volume and decrease in duration below 2000 meters, with some low-elevation bands losing over 30% of their total snow-water storage. In contrast, high-elevation zones (>2500 m) are experiencing increased accumulation (needs, but a continued shortened snow season. However, the increase in snow water storage at high elevations requires careful interpretation due to methodological constraints and systematic overestimation of high elevation precipitation by ERA5. Second, we show that this shorter snow season is not just an artifact of earlier spring melt, but is primarily driven by a delayed onset of snow accumulation in early winter. 

These elevation-dependent changes and loss of the seasonal snowpack highlight a fundamental shift in the hydrological regime of the Po River Basin, with significant implications for the timing and volume of runoff and the future availability of water in the region.Therefore, the Po River Basin is moving from a stable to a more volatile system.

Note: To know more, click on the picture (study area) above to read our preprint.