Examining snow avalanches using Sentinel-1 radar data: case of Gissar-Alai Mountain Range

The investigation of avalanche activity in mountainous regions manifests an important aspect of public and infrastructure safety and protection, with particular attention to avalanches in hard-to-reach and poorly studied areas, like the Gissar-Alai Mountain Range. Remoteness, inaccessibility and increased cloudiness during the high avalanche season make field observations and applying optical satellite imagery for studying the avalanche activity in the Gissar-Alai extremely difficult. In such setting, radar technologies allowing to receive data regardless of weather and lighting conditions offer the best solution. The article describes the methodology for processing radar images of the Sentinel-1 satellite, as well as the results of decoding avalanche deposits in the Zeravshan, Gissar, Turkestan and Alai Ranges during the 2021-2022 season. The method underwent verification based on the Sentinel-2 multispectral data. In addition, the article characterizes the peculiar features of avalanche activity for each of the Gissar-Alai ridges, including the distribution of avalanche deposit zones by absolute heights, as well as slope steepness and exposure.