Abstract
Documenting long-term snow cover changes at high spatial resolution is especially challenging in mountain environments due to limited high-elevation ground observations and the coarse resolution of current climate models. This paper presents a dataset of snow melt-out dates (SMOD) at 30-m spatial resolution for two periods-the 1990s (1985-1996) and the 2010s (2011-2022)-across temperate European mountain ranges (Pyrenees, European Alps, and Greater Caucasus), derived from Landsat time series. To address the limited number of observations in the Landsat archive, data were aggregated over 12-year periods, enabling assessment of SMOD changes over four decades at a spatial resolution relevant to above-treeline ecosystems. The SMOD dataset was validated using snow depth station records (R(2) ~ 0.75, MAE ~ 7 days) and soil temperature data (R(2) ~ 0.7, MAE ~ 10 days) from the Pyrenees and European Alps. Potential applications of the dataset extend beyond alpine ecology, with possible contributions to risk assessments, hydrology, and snow climatology in the context of climate change.