Disastrous debris flows connected with glacial processes and defense methods against them in Kazakhstan

Abstract

Due to climate warming which came after the ending of the Small glacial age, surface and subsurface reservoirs started to form on the mo - raine-glacial complexes of the northern slope of the Zailiysky Alatau Mountain Range. Breakout of these reservoirs led to disastrous debris flows in the middle of the 20th century. Up to 60s of the 20th century rainfall-caused debris flows with rare frequency were considered to be of main danger and construction of large check dams forming debris-flow reservoirs was assumed as a basis of defence strategy against debris flows. The sharp activation of debris flows connected with glacial processes required revision of the existing defence strategy against debris flows. That is why designing and building the small reservoirs for detention of glacial outburst water in the high-mountain zone and preventive measures aimed at emptying lakes on the moraine-glacial complexes started.