Alps are Losing Snow
Photo credit: John WaniSeasonal 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.
Analyzing Three Decades of SWE Changes
This study provides the first comprehensive long-term (1991–2021) analysis of Snow Water Equivalent (SWE) changes in the Po River District, Italy, one of Europe’s 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, 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 but a continued shortened snow season. 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.
© 2025 John Mohd Wani. All rights reserved.
(Note: High-elevation zones (>2500 m) are experiencing increased accumulation, but this requires careful interpretation due to methodological constraints and systematic overestimation of high elevation precipitation by ERA5.)
Implications for the Po River Basin
These elevation-dependent changes highlight a fundamental shift in the hydrological regime of the Po River Basin. The loss of seasonal snowpack has significant implications for the timing and volume of runoff and the future availability of water in the region. The Po River Basin is moving from a stable hydrological system to a more volatile system.
Read the Full Preprint
To know more and see the full analysis, Read our preprint.
References:
Dall’Amico, M., Tasin, S., Di Paolo, F., Wani, J.M., et al. (2025).
30-years (1991-2021) Snow Water Equivalent Dataset in the Po River District, Italy.Scientific Data, 12, 374.
