Spatially resolved estimates of glacial retreat and lake changes from Gepang Gath Glacier, Chandra Basin, Western Himalaya, India

Glacial lakes dynamics has a concomitant impact over glacial retreat, mass change and glacial lake outburst floods (GLOFs) events. Recent warming led increase in glacial retreat at High-Mountain Asia (HMA) which has accelerated the formation of moraine-dammed glacial lakes; however, their relative potential for catastrophic events i.e., GLOF, are still a matter of detailed research. In the present study, the changes are assessed at the terminus position, glacier area and associated proglacial lake of Gepang Gath Glacier (GGGL), Chandra basin, western Himalaya, India, using multi-years satellite dataset of Landsat series (TM, ETM+ and OLI, 1989–2017). The results of glacial volume estimations using volume-area scaling method suggests ∼0.28 km3 of ice volume loss between 1989 and 2017. The glacier has retreated ∼846 m with an average rate of 30 m a−1 and lost ∼0.73 ± 0.05 km2 frontal area from 1989 to 2017. However, the glacier has not shown uniform retreat rate. Between 1989 and 2000 glacier retreat about ∼14 m a−1 and the rate was increased gradually to ∼38 m a−1 (2000–2009) and ∼50 m a−1 (2015–2017). The calculated proglacial lake area has expanded ∼44 % and estimated equilibrium line altitude (ELA) rise was 54 ± 12 m, during the study period. The study explains that the continuous expansion of proglacial lake and ice loss can be dangerous to downstream region. It is concluded by underlining the importance of glacier-lake relationships to predict the glacial lake behavior and understand the probability of lake catastrophic events i.e., GLOF and associated hazards.