Preventive avalanching in the Khibiny has been carried out for almost 90 years. The experience accumulated in this area allows evaluating it critically. The methods of preventive avalanching in the Khibiny Mountains, in other regions of Russia, and other countries are analyzed. The most widely used methods are those based on the effects of explosions on the snowpack stability. Despite such long-term experience, a scientific basis for their use is not sufficiently developed, and there are no rational methods for their application. The insufficient knowledge of the mechanisms of avalanche release and short-term impulse loads on the snow stability, as well as the high spatial variability of snow characteristics that control its stability at an avalanche starting zone, and the almost complete absence of their measurements are the main obstacles to solving these problems. The development and realization of a state program aimed at improving the effectiveness of artificial avalanche release could make the current situation better.
The study was carried out to estimate the spatial variability of snow cover depths in avalanche centers of the mountain slopes of Svalbard. Accounting for the variability is necessary for monitoring the snow cover depths in the avalanche centers and evaluating the snow cover stability on the slope. The main tasks of the work were to evaluate the variability parameters and compare them with similar estimates obtained in other regions. In contrast to conventional snow surveys, thickness measurements were carried out more frequently (with resolution of every 1 m) in profiles (eight profiles in total), not exceeding the characteristic linear size of the avalanche origin zone (up to 100 m(2)). Spatial variations of snow cover thickness in each profile are considered as the realization of a random process. Data of the spring measurements of 2015 were used to estimate the mathematical expectations, variances, and autocorrelation functions of the snow cover depth on the Mount Olav slopes. Comparison of parameters of variability with those obtained in different mountain regions of Russia with the similar underlying surface, shows that the variability on Svalbard are the most similar to the variability in the Khibiny Mountains. Although the scattering and coefficients of variation obtained in the Khibiny Mountains are slightly larger, the spatial coherence of the snow cover depths is the lowest on Svalbard. Estimates of the correlation radii are within the range of 2-6 m. With such variability any deterministic estimation of spatial snow accumulation with the help of remote measurement stakes is impossible. The obtained parameters of the spatial statistical structure of the snow cover thickness allow using statistical modeling for the interpretation of point measurements. In that case, uncertainty of snow cover thickness data in places where measurements were not made will be reflected in their probabilistic estimation.
A possibility of space-temporary short-term forecast-diagnosis of dry sublimative recrystallization and mixed (recrystallization plus fresh snow) avalanches is under consideration. The special discriminate analog–macrophysical models of the short-term background forecast is verified on correlation degree with probabilistic zoning of avalanche site № 22 in Khibiny. Аs a result we have correlation coefficients of order –(0.6÷0.7). The statistical significance of correlation coefficients (an order of 0.02–0.07) are checked and a conclusion on likelihood of assumed hypothesis is made. So by the current and predicted meteorological data such kind of forecast for such genetic avalanche types release in concrete sites becomes possible. The short-term forecast function transformation of the examined in the article avalanche types into long-term ones by averaging perennial realized forecast function values on slipping optimal 5-years intervals shows avalanche activity trend with probable 8–10 and 32-years harmonics during selected observation period. But in comparison with purely dry and wet fresh snow avalanches forecast analysed before the examined here above types are less precisely predicted. So it is needed an improvement of correspondent forecast functions on the base of theory contribution and future observations by increasing their series
Period of warming is registered at Khibiny Mountains in the end of XX century. Sensible rise in temperature occur in winter. The one of general indicators of present climate changes is multiyear dynamic of nival processes not only for contrast high-mountain conditions but also for more temperate green belt. Compatible variability of both data sets from high-mountain (1050 m) and green belt (320 m) stations allows to full appreciation of present changes. The results of data evaluation shows stability of snow cover characteristics against changing of winter temperature conditions and avalanche activity.
Thickness, density, shearing strength, and temperature of snow on mountain slopes are considered as stochastic fields or processes. Parameters of these fields (processes) were estimated in several geographical regions. Errors of snow stability estimation are shown to be depending on the above parameters, quantity of point measurements, and the measurement technique. Errors of different methods of space and time interpretation of measurements of the snow characteristics are discussed. Results of these studies performed on slope of the Khibiny Mountains, the Altai, the Baikal Mountains, and the Caucasus are presented in the article. Monitoring of the snow cover stability on slopes and the avalanche forecasting are the most difficult actions to be carried out in areas with great spatial variability of snow. The Khibiny Mountains are first of all such area among other ones.
IV International Conference «Avalanches and Related Issues»
Thickness, density, shearing strength, and temperature of snow on mountain slopes are considered as stochastic fields or processes. Parameters of these fields (processes) were estimated in several geographical regions. Errors of snow stability estimation are shown to be depending on the above parameters, quantity of point measurements, and the measurement technique. Errors of different methods of space and time interpretation of measurements of the snow characteristics are discussed. Results of these studies performed on slope of the Khibiny Mountains, the Altai, the Baikal Mountains, and the Caucasus are presented in the article. Monitoring of the snow cover stability on slopes and the avalanche forecasting are the most difficult actions to be carried out in areas with great spatial variability of snow. The Khibiny Mountains are first of all such area among other ones.
