Evidence for enhanced mechanical weathering associated with seasonally late‐lying and perennial snow patches, Jotunheimen, Norway

At two snow patch sites in Jotunheimen, Norway, direct evidence of surface fracturing and splitting of boulders was collected to quantify spatial variations in the amounts of mechanical weathering associated with snow patches. Transects between external control and internal sites display a 3‐5‐fold increase in the percentage of clasts affected by mechanically induced fracture processes. Up to 50% of clasts within the internal areas of the snow patches exhibit either surface flaking or more severe fracturing; this contrasts with up to 15% of clasts exhibiting evidence of mechanical weathering at the snow patch peripheries. The results indicate that the snow patches significantly enhance mechanical weathering processes and that maximum mechanical weathering is associated with the average annual retreat position of the snow margin.