Lakes expansion and emergence of potentially dangerous glacier lakes in Astore River Basin, Western Himalaya during 1993-2021

Abstract Glaciers in High Mountain Asia ensure freshwater to billions of people downstream but this supply is dwindling owing to rapid melting due to climate change. On the same note, glaciers in the Astore River Basin, of the Upper Indus Basin (UIB), are rapidly melting leading to accelerated expansion of glacial lakes, emergence of new glacial lakes, and increasing the risk of Glacial Lakes Outburst Floods (GLOFs). This study investigates seasonal and decadal fluctuations in glacier lakes using Landsat data between 1993 and 2021 and differential Global Positioning System (dGPS) field observations. We found an increase in the number of glacial lakes and areal expansion of existing glacial lakes in the study area. During the 2021 ablation period (Jun-Oct), the number of contemporary glacial lakes grew fivefold (18 to 100), while the area expanded sixfold (0.62 to 3.86 km2), the newly developed lakes were greater than 0.01 km2. Over the past decade, PDGLs have doubled. To lessen the risk of GLOF, continuous monitoring of these lakes is necessary in the future. The implementation of GLOF monitoring and early warning systems, as well as sustainable water management practices, ought to be prioritized for mitigation and adaptation measures.