ИСТИНА

Following by glacier downwasting, glacier lakes are appearing and expanding in many glacierized mountains in the world. Thus glacier lake outburst floods (GLOFs) have no historical precedent in some cases which lead to uncertainties in hazard assessment. Here we analyzed situation in the Russian Caucasus where glacier demonstrate rapid and accelerating downwasting. Steep and loose sediment rich valleys provoke formation of debris flows even in case of small outburst volume. The most significant GLOF since 2000 happened on 1st September, 2017. Thinning of the Bashkara Glacier snout lead to destabilization of moraine dam, and extreme rainstorm impacted as a GLOF trigger. Considering similar tendencies (glacier thinning and increase of rainstorm frequency) in many regions including High Mountain Asia we propose that GLOFs caused by similar reasons might become much more frequent.