Four of five high-risk glacial lakes in Arunachal expand over decade, satellite study finds
A satellite-based assessment of five glacial lakes in Arunachal Pradesh’s Tawang district has found that four have expanded over the last decade, with one lake
A satellite-based assessment of five glacial lakes in Arunachal Pradesh’s Tawang district has found that four have expanded over the last decade, with one lake showing particularly rapid growth, adding fresh evidence to concerns over the threat posed by glacial lake outburst floods (GLOFs) in the eastern Himalaya. The analysis—a report and not a peer-reviewed study—conducted by Noida-based geospatial intelligence firm Suhora Technologies, examined five lakes in the Mago Chu basin that have been classified by the Disaster Management Authority (NDMA) as ‘high-risk’ or ‘very high-risk.’ The assessment comes amid heightened attention on glacial hazards in the region following a recent risk evaluation by the Centre for Earth Sciences and Himalayan Studies (CESHS), Arunachal Pradesh, and broader efforts by authorities to identify potentially dangerous glacial lakes in the Himalaya. Using imagery from ICEYE, PlanetScope and LISS-IV satellites, Suhora compared the extent of the lakes between 2016 and June 2026. In a press statement accompanying the analysis, the company said that “four out of five lakes have expanded, reflecting a general trend of glacial retreat and meltwater storage.” However, it cautioned that “lake expansion does not directly indicate a flood event” and said the findings instead highlighted “the importance of regular monitoring and further assessment to better understand future risks.” Among the lakes analysed, Sanhapo Lake showed the most significant growth.
Suhora estimated its area at 78.07 hectares in 2019, increasing to 88.81 hectares by mid-June 2026. The company said that while uncertainties remain regarding its historical extent because of ice cover visible in 2016 imagery, the lake has exhibited sustained expansion in recent years. Given its size and continued growth, Suhora identified it as the highest-priority lake among those assessed for detailed hazard modelling, continuous monitoring and possible early-warning systems. The remaining lakes showed more modest changes. Two lakes categorised by the NDMA as “very high risk” expanded by about a hectare over the decade, while Dharkha Tso, listed as “high risk”, also recorded gradual growth. A fifth lake remained broadly stable over the observation period. Commenting on the findings, Amit Kumar, co-founder and chief operating officer of Suhora Technologies, said satellite observations were increasingly important for monitoring remote mountain regions where field access was often difficult. “By comparing satellite imagery across multiple years, it is possible to track changes in glacial lake extent with the monsoon season approaching, continuous observation of glacial lakes becomes increasingly important”, he added. Anil Kulkarni, glaciologist and distinguished fellow at the Divecha Centre for Climate Change, Indian Institute of Science, Bangalore and who wasn’t connected to the study, said the observed expansion warranted attention but should not be interpreted as evidence of an impending disaster.
The BriefWire