Forecast of debris flow hazard in the northern side of the greater caucasus

Abstract

The paper presents a method of a short-term forecast for meteorologically initiated debris flows of different genesis. A diversity of an environment of Greater Caucasus predetermines a wide spectrum of geologic-geomorphologic processes and non-reliable meteopredictors which cause debris flows formations. The water impulse which causes the debris flows formation is connected with showers (pluvial genesis) and also with glaciers thawing and snow (glacial genesis and snow genesis). However debris flows of polygenic meteo genesis, glacial-pluvial and snow-pluvial are the most widespread. The last is connected with fluctuation of the air humidity and weather temperature that makes forecasting of the hazardous events considerably difficult.
The proposed method of the debris flows forecasting is based upon numerical values resulted from continuous long-term observation, since 1951 up to 2009. On the first stage we classified river basins by prevailing debris flows genesis (pluvial, glacial-pluvial and etc.).The numerical mapping of the territories was made according to above mentioned basins classification was made. The main meteo predictors for each group of basins with homogeneity of debris flows formation and their critical values were obtained. The prediction of the dates of debris flows events rely on a short-term daily temperature and precipitation forecasting.