Распространение пещер с многолетним льдом на Южном Урале и в Предуралье

The paper presents systematized information about distribution of karst caves containing accumulations of old ice and snow outside the zone of continuous permafrost. It was found that among total number of 1,150 caves in the region known by January 1, 2022, the old ice had been registered only in 68 (6%) ones. Distribution of them is conditioned by the general mechanisms of development of karst cavities, but a number of additional conditions are required to form the snow-ice accumulations within them. Ice and snow are formed mainly in bag-shaped caves confined to the middle and upper parts of river valleys, or in caves located in the upper reaches of the ravines on the watershed areas, the entrances to which are represented by wells, deep karst channels or are located in sinkholes. The intensity of accumulation and conservation of snow and ice in caves, under other favorable morphological and hydrogeological conditions, is directly dependent on the area of the entrance to the cave and the slope of the floor at its entrance. Snow-ice accumulations are represented by ice bodies, stalactites and stalagmites, hoarfrost and large ice crystals, snow, firn and ice. The most developed of them is ice. The maximum recorded area of the cave ice is 5000 m2, its thickness is 11 m, the depth of penetration of glaciation deep into the karst massif from the entrance reaches 70 m, and the length is 250 m. Factors that reduce the accumulation of snow and ice in the caves of the region include: periodic flooding of karst cavities, shortening of woody vegetation on the surface above them, and cave attendance. On the case of the Askynskaya cave, the dependence of the state of snow-ice accumulations on local climatic conditions and the degree of anthropogenic load has been determined. It is recommended to monitor the state of snow and ice formations in the rarely visited Ledyanaya-Lipovaya cave with the most thick icing, in order to establish a correlation between the state of glaciation of the cave and changes in local climatic conditions.Систематизированы сведения о распространении карстовых пещер с многолетними снежноледяными образованиями. Установлено, что из всех известных пещер региона только в 6% зафиксированы многолетние лёд и снег. Распространение таких пещер обусловлено общими закономерностями развития и распространения карстовых полостей. Однако для формирования в них снежно-ледяных образований требуется ряд дополнительных условий