Avalanche caused catastrophes on the mountainous rivers

Abstract

Alongside with the danger of snow avalanching for the objects and population, the subsequent phenomena caused by the avalanching are not less serious. One of such reasons can be the choked lakes and outflash floods on the mountainous rivers. The investigation of this matter has revealed the following. : 1. The spreading of this phenomena is typical for all mountainous regions of the world with the water courses and snow avalanches available. 2. Its danger is in the unexpected occurrence and catastrophic nature of the flood. 3. With the great number of the avalanche slides blocking in the mountainous river beds the occurrence of the outflash floods is not observed in all cases. Using the real data collected in the Western Tien Shan mountains the numerical models were elaborated which allowed to calculate the volumes of the checked lakes, the time of their outbreak, the maximum levels of the outflashing floods and the length of their spreading. The elements of the river bed morphometry, of the avalanche centers, the water and snow conditions are used in the calculations. The comparison between the real and calculated data proves the satisfactory convergence and makes it possible to begin the forecasting of such dangerous phenomena on the basis of the standard hydrometeorological data.