Specific changes of the Kolka Glacier (the North Caucasus) from 2002 to 2016

Abstract

The process of filling the bed with ice with steep lateral tributaries, which lost support, began almost immediately after the catastrophe on the Kolka Glacier in 2002. Currently, three streams of ice have closed in the rear zone of the circus, forming a single ice massif on the bed. The dimensions of the glacier vary under the influence of both new conditions for the accumulation and melting of ice, and the features of the dynamics of the ice masses filling the vacated bed. This paper describes the next stage of the state of the new Kolka glacier – relative stabilization – and analyzes the features of the process of its recovery based on ground‑based observations, modern space imag‑ ery materials, and calculations of changes in summer air temperatures and winter precipitation in the glacier area at the beginning of the 21st century. In recent years, the rate of increase in the area of the glacier does not exceed 0.015 km2 per year. By September 2016, its area reached 1.11 km2, the volume – about 0.044 km3. The conditions for the formation of a new glacier on the empty bottom of the circus differ significantly from the previous ones – when Kolka was restored in the 1970s after a pulsation. In addition to the background increase in summer tem‑ peratures, the thermal balance in the circus has changed due to an increase in the area of the open surface of the bed and lateral moraine, which increases the melting of ice. At the same time, the growth of the moraine cover on the glacier restrains the melting process. Rockfalls and avalanches enrich the glacier with detrital material with greater intensity than in the 1970s. The conditions of accumulation also changed – the volume of food supplied from the hanging glaciers decreased from the previous 31% to 17%. Fumarolic activity in the crown area of the starboard side of the circus is preserved and this prevents the restoration of these glaciers.