AN ASSESSMENT OF THE SIMILARITY OF SNOWSTORM AVALANCHING IN THE KHIBINY MOUNTAINS

Abstract

In practice, forecasting of avalanche occurrences in a single avalanche path is usually subjective based on background avalanche and weather forecasts, data on the location and topography of the avalanche starting zone, as well as available data on the snowpack in it. Moreover, forecasters sometimes identify avalanche starting zones, in which, according to their opinion, avalanche formation is similar. It is generally believed that avalanche formation occurs similarly in avalanche starting zones similar in morphology and morphometry, as well as having similar exposure. The aim of the work was to establish a quantitative relationship in the avalanche formation of snowstorm avalanches in 22 avalanche starting zones located in an area of about 25 km2 located in the southern part of the Khibiny Mountains. The study was based on long-term observations of avalanches in this area. As a measure of the proximity of avalanche formation in two avalanche starting zones P (i / j), we used the conditional probability of avalanche formation in avalanche starting zone i, if an avalanche formed in avalanche starting zone j. As the study showed, correlations between avalanche formation in various avalanche starting zones are statistically significant, but, as a rule, rather weak. The most similar formation of snow avalanches occurs in the starting zones having a similar exposure. In addition, the deformations of the air flow in the mountain system and the size of the snow drift zones, as well as the spatial variability of the physical and mechanical characteristics of snowpack in avalanche starting zones, also affect. A methodology for probabilistic diagnosis and forecasting of snowstorm avalanches using avalanche starting zones-indicators is proposed.