Dozens of glacial lakes have formed across northern India in the last three decades, while existing lakes have expanded rapidly, highlighting the need to monitor a landscape reshaped by climate change.
As the recovery operation continues in Nepal in the aftermath of catastrophic flooding that struck the country on 26 August 2026, a recent satellite study reveals glacial lakes are multiplying and expanding in the Himalayas as glacier ice melts, raising concerns that more devastating floods will hit the region in the future.
The paper Alarming trends: rapidly growing and recently formed glacial lakes in the Alaknanda Basin, northern Indian Himalayas , is published in De Gryter's international journal Open Geosciences .
The study used space-based observations from the Landsat and Sentinel-2 satellites to map changes in 74 glacial lakes in the Alaknanda Basin in the western Himalayas of India between 1994 and 2023. The results show just how quickly the landscape is changing: melting glaciers are forming and feeding high altitude lakes that can, under the right conditions, suddenly release large volumes of water.
The combined area of 24 glacial lakes – larger than 0.01km2, the low cut-off point used in the methodology to exclude small seasonal waters – grew from 0.97km2 in 1994 to 1.62 km2 in 2023 – an increase of 67% in 30 years.
But it's not just a case of existing lakes getting bigger. The author identified 57 new glacial lakes formed during the study period, bringing the total number of lakes in the basin to 131. Of these, 18 newly were larger than 0.01km2.
Some individual lakes have grown particularly rapidly. Vasundhara Lake expanded by 261% between 1994 and 2023, while Balbala Lake grew by 119%.
The study also identified 27 glacial lakes showing notable growth, including one upstream of the important pilgrimage site of Badrinath. The author also cites the very rapid growth of Vasundhara Lake as needing close attention. These lakes warrant continued monitoring and further assessment because changes in their size and stability could affect areas downstream.
Glacial Lake Outburst Floods, or GLOFs, happen when water held back by ice, rock or sediment is suddenly released carrying water, mud and debris with potentially destructive force.
The recent disaster in Nepal was not itself a conventional GLOF, but it demonstrates the extraordinary consequences that sudden high-mountain flood events can have on communities and infrastructure. Nepal's government says the August floods caused widespread damage to houses, roads, bridges and hydropower facilities.
"The recent flooding is a reminder of how important it is to continuously monitor high-mountain environments where multiple hazards including extreme rainfall, glacial lake expansion, slope instability and seismic activity can interact and potentially amplify downstream impacts," says study author Dr Aayushi Pandey from Charles University, Prague, Czech Republic.
"Satellite data are extremely valuable for screening a large and inaccessible region. They allow us to identify newly formed lakes, measure changes in lake area, identify rapidly expanding lakes and shortlist those that need detailed investigation," she says. "But that's not the complete solution. Field measurements are essential to determine lake depth and volume, assess slope stability, understand drainage pathways and glacier–lake interactions, and improve flood modelling.
But this work requires substantial logistical and financial support, including stronger transboundary scientific cooperation and data sharing, because glacial-lake and flood hazards do not follow political boundaries and should be addressed as a shared regional concern," says Pandey.
The paper can be found here: https://doi.org/10.1515/geo-2025-0974
