Spatiotemporal dynamics of snow cover characteristics in the Magadan region for avalanche hazard assessment

Given the complex mountain terrain and the insufficient network of meteorological stations, assessing and forecasting avalanche hazard in the Magadan Region is a pressing issue. This study examines patterns in snow cover characteristics (average and maximum snow depth, dates of establishment and disappearance) at 1) gauges located on mountain passes or at altitude " 900 m along the Kolyma and Tenkinskaya highways, and 2) at the nearest meteorological stations of the Roshydromet in 2022–2025. For two test sites, avalanche runout distanceswere calculated according to regulatory documents based on data from the monitoring network and Roshydromet stations in 2025. This study utilizes the data from the automatic snow cover monitoring network, which was installed in the Magadan Region in 2022–2025 (altitude range of 162–1232 m). Data from field studies were also used. Avalanche characteristics were calculated in accordance to regulatory documents. For the first time, an automatic snow cover monitoring network was installed in the Magadan Region, and data obtained in 2022–2025 were analyzed. This revealed significant discrepancies in snow characteristics between Roshydromet stations and high-altitude sections of the monitoring network. It was found that snow depth on mountain passes can be 2–3 times higher than that of the reference station, and the duration of snow cover can increase by 25 days or more. The insufficiency of the existing Roshydromet network for accurate avalanche hazard forecasting was demonstrated. Using avalanche start zones near the Gusakova Pass as an example, it was demonstrated that applying data from the automated network allows for accurate assessment of avalanche runout distance, whereas calculations based on meteorological station data underestimate actual figures by 1.5–2 times. The obtained results can form the basis for recommendations for developing a monitoring system and avalanche protection measures along the most dangerous sections of Magadan Region's highways.