Glacier retreat in the Indian Himalayas is causing the rapid expansion of glacial lakes and creating dozens of new ones. Research by Dr. Aayushi Pandey from the Department of Physical Geography and Geoecology of the Faculty of Science, Charles University, combines 30 years of satellite data with field surveys at high-risk Lake Balbala. Warning of catastrophic floods, the study resonated across more than 30 global media outlets.
Unique Combination of Local Knowledge and Advanced Satellite Research
Global climate change is driving severe glacier retreat across high-altitude mountain ranges. In the Indian Himalayas, this process forms hazardous natural water reservoirs that pose an ongoing threat to downstream communities. A major new study by Dr. Aayushi Pandey, a native of India working at the Department of Physical Geography and Geoecology at the Faculty of Science, Charles University, brings crucial findings on the extent of this hazard.
Dr. Pandey combined deep local familiarity with the Indian environment and advanced remote sensing methods. Her study targeted the Alaknanda River Basin in Uttarakhand, India - a vital freshwater source for millions of people that faces heightened vulnerability to natural disasters.
Alarming Numbers: 57 New Lakes and Multi-Fold Growth
Analysis of satellite imagery spanning 1994 to 2023 revealed that the total surface area of 24 main monitored lakes increased by 67% (from 0.97 km² to 1.62 km²). Retreating glaciers also formed 57 brand-new lakes, bringing the total count in the basin to 131. These reservoirs are impounded by unstable dams of loose rock and debris. If breached, they unleash catastrophic Glacial Lake Outburst Floods (GLOFs) that sweep away everything in their path.
The study examined the two fastest-expanding lakes in detail:
- Lake Vasundhara: Surface area grew by 261% between 1994 and 2023 (and by 352.5% since its formation in 1972).
- Lake Balbala: Grew by 119% over the same period, representing an expansion of over 800% since 1980.
At Lake Balbala, located at an extreme altitude of 5,549 meters above sea level, Dr. Pandey performed the first documented ground field survey in history. The hazard index of 0.855 places Lake Balbala in the very high-risk outburst category due to unstable moraine structures and surrounding slopes. A potential outburst would directly threaten downstream towns and the major pilgrimage destination of Badrinath.
Satellites Are Not Enough
The key innovation of this work lies in showing that remote space observation alone cannot accurately predict outburst hazards. Field verification on the ground is essential to assess real flood risks.
“Satellite data is extremely valuable for monitoring vast and inaccessible mountain areas. However, it is not a complete solution. Precise flood risk modeling requires direct field measurements of lake depth and volume, as well as slope stability assessments,” explains author Dr. Aayushi Pandey. She adds that these risks ignore national borders and demand international scientific collaboration.
Extensive Global Resonance Across More Than 30 Outlets
The urgent findings by the Charles University researcher generated impressive global media interest. Over 30 international media outlets, press agencies, and scientific news platforms across more than ten countries covered the study. Outlets include major US platforms such as Earth.com and Scienmag, the UK's EnvironmentJournal, Poland's national agency PAP and Polskie Radio, and Thailand's daily newspaper The Nation. This widespread international coverage underlines the global significance of research conducted at the Faculty of Science, Charles University.
Bibliographic Citation: Pandey, A. (2026). Alarming trends: rapidly growing and recently formed glacial lakes in the Alaknanda Basin, northern Indian Himalayas. Open Geosciences, 18(1), 20250974. https://doi.org/10.1515/geo-2025-0974
Links:
https://www.nationthailand.com/sustaination/40071008
https://scienmag.com/melting-himalayan-glaciers-are-quietly-building-a-flood-threat-downstream