Rock glaciers in Peru are key components of mountain permafrost, playing a fundamental role in terrain stability and water availability. However, their dynamics and the associated feeding processes, such as snow persistence, remain poorly understood. This study assesses the relationship between permanent snow cover and rock glaciers in the Peruvian Andes, focusing on its potential influence on the natural hazards characteristic of these regions.
More than 1,200 rock glaciers classified as active or transitional were analyzed using the Maximum Snow Extent (MSE) layer from the MOD10A2 MODIS product from 2002 to 2021. Permanent snow cover was defined as areas with a persistence equal to or greater than 80%. The results indicate that approximately 12% of the total rock glacier area (~75 km²) is covered by persistent snow, with a higher concentration in active rock glaciers (~68%). These areas of long-lasting snow cover are primarily located in the southern Peruvian Andes, where lower temperatures due to higher altitude favor ice preservation.
From a natural hazard perspective, permanent snow cover can play a dual role. On one hand, it contributes to maintaining the internal ice content of rock glaciers, regulating their thermal and structural stability. Besides, variations in snow persistence may influence permafrost degradation, affecting terrain stability and increasing the likelihood of triggering geomorphological processes such as landslides and ground subsidence on steep slopes.
These findings highlight the importance of snow cover in the evolution of rock glaciers and their dynamics in relation to natural hazards in the Peruvian Andes. The identification of areas with high snow persistence provides relevant information for managing these environments, particularly in the current context of climate change and its impact on mountain landscape stability.