Академическое издательство «Гео»

Glacial lake outburst flood (GLOF), debris flood, Caucasus

KRIOSFERA ZEMLI, 2018, Vol. XXII, № 2, p. 70-80

The outburst of Bashkara glacier lake (Central Caucasus, Russia) on September 1, 2017

S.S. Chernomorets1, D.A. Petrakov1, A.A. Aleynikov2, M.Y. Bekkiev3, K.S. Viskhadzhieva1,
M.D. Dokukin3, R.K. Kalov3, V.M. Kidyaeva1, V.V. Krylenko4, I.V. Krylenko1, I.N. Krylenko1,
E.P. Rets5, E.A. Savernyuk1, A.M. Smirnov1

1Lomonosov Moscow State University, 1, Leninskie Gory, Moscow, 119991, Russia; devdorak@gmail.com
2SCANEX R&D Centre, 1, Kiev highway, Business Park “Rumyantsevo”, 8 entrance, office 732, Moscow, 108811, Russia
3High-Mountain Geophysical Institute, 2, prosp. Lenina, Nalchik, Kabardino-Balkaria Republic, 360030, Russia
4 Shirshov Institute of Oceanology, RAS, 36, Nahimovskiy prosp., Moscow, 117997, Russia
5 Institute of Water Problems, RAS, 3, Gubkina str., Moscow, 119333, Russia

The outburst of Bashkara Lake on September 1, 2017 reflects the current stage of glacier downwasting when the stable regime of lakes, debris complexes and glaciers is disturbed. We have estimated the parameters of the lake outburst as well as threshold and trigger conditions using ground-based and aerial observations, satellite imagery analysis, and instrumental data obtained from a drone, an echo-sounder, an automatic weather station, and a water level datalogger. An abnormal shower with 100 mm of precipitation happened during a night from August, 31 to September, 1 following the previous (August, 30–31) 45 mm rainfall, has been recognized as trigger of the lake outburst. The volume of the liquid phase of the debris flood was about 1.1 mln m3, including water released during the lake outburst (0.8 mln m3). In the valley of the Adylsu River, 0.35–0.50 mln m3 of debris was entrained into the flow. Based on this research we propose recommendations on measures how to prevent emergencies which still could take place in the area.

Glacial lake outburst flood (GLOF), debris flood, Caucasus

DOI: 10.21782/KZ1560-7496-2018-2(70-80)