Remote sensing-based hazard assessment of glacial lakes in Sikkim Himalaya

Glacial lake is a water body formed in/under/besides and/or in front of a glacier due to glacial dynamics. Such high-altitude glacial lakes are hazardous to humanity and infrastructure as they can drain instantaneous and create devastating floods in the downstream. The formation of moraine-dammed glacial lakes and glacial lake outburst flood (GLOF) is major concern in countries such as Bhutan, Tibet (China), India, Nepal and Pakistan. The temporal satellite data analysis from CORONA to LISS III shows the glacier receded 1.9 km from 1962 to 2008 and the formation of a moraine-dammed glacial lake at the snout of South Lhonak glacier, Sikkim Himalaya. The lake outburst probability shows a very high value of 42% for the lake and peak discharge estimated using the empirical formula shows a discharge of 586 m3/s. A systematic inventory of glacial lakes using high-resolution satellite data and in situ field survey is recommended and adaptation measures like early warning systems and mitigation measures are required in potential GLOF areas.