OCR Text |
Show Conclusions Because of the prolonged and snowy winters, with varying conditions of snow deposition ( precipitation) and frequent windstorms, the Kirovsk area is particularly adapted for observation of all the varieties of snow forms and for following all the transformations taking place in snow. The medium elevation of the mountains, and their relative accessibility, the great number of avalanche sites, and the avalanche frequency here, are all factors that aid in gaining knowledge about avalanches in general. All these factors in combination make the Chibin area more advantageous than other mountainous regions of the USSR for avalanche study and for gaining scientific and practical information about this interesting and stern manifestation of nature. To be sure, observations and measurements made in Chibin will not necessarily apply to experience under other geographical conditions. Properties specific to avalanches here may have little or no significance elsewhere, and peculiarities unobserved or of no consequence around Chibin may take on importance in other areas. In Chibin, for example, no hoarfrost ( snow) avalanches are ever observed, although hoarfrost ( snow) gathers here in layers 1 m thick along mountain tops and on snow cornices. Nor have there been any instances here of the " layered" avalanches that occur in the Caucasus, in the area of the Caucasian Reserve, where wet snow breaks away successively, layer by layer, during the day, according to A. A. Nasimovich. Under differing relief conditions, a wet snow avalanche may have the same high velocity as one of dry snow, particularly where part of its descent is through the air, over precipices, etc. This aerial drop of avalanches, so often mentioned in the literature on Alpine avalanches, is not observed here in Chibin where the slide slopes are more gradual ( even) from top to bottom. The drop from steep heights of discrete snow masses, or even snow cornices, can not be counted as aerial avalanches. In localities of abundant snowfall and warm winters, moist snow avalanches may be on an extremely large scale, whereas such slides are of insignificant size around Chibin. But the unexpected can happen even in Chibin. Not only are large, destructive avalanches of dry, freshly fallen snow possible here, but also those resulting from the precipitation of large amounts of moist or wet snow on a frozen snow crust. We still have much difficult study and investigation ahead of us on the nature of snow, and on its transformations and its physical and mechanical properties, all of which in combination have a bearing on avalanche origin. Also requiring further study are all the different varieties of avalanche causes, their external features, their destructiveness, and the various measures to be taken against this hazardous natural phenomenon. - 64- |