High-Risk Glacial Lakes Identified in Arunachal Pradesh Amid Climate Concerns

A new study has identified two high-risk glacial lakes in Arunachal Pradesh, with 36 others at medium risk, amid growing concerns over climate change. The research highlights the potential for devastating glacial lake outburst floods (GLOFs) as temperatures rise and glaciers retreat. With significant increases in the number and area of lakes observed, the study calls for enhanced monitoring and preparedness measures to mitigate risks to downstream communities and infrastructure. Researchers emphasize the importance of understanding the dynamics of these lakes and the potential impacts of GLOFs, urging for continuous assessment and community awareness initiatives.

By Narendra Chaudhary Sep 3, 2026, 09:46 IST

Introduction to GLOF Risks

Representational Image

Guwahati, Sept 3: Recent research highlights the alarming threat of glacial lake outburst floods (GLOFs) in the Himalayan region, pinpointing two high-altitude lakes in Arunachal Pradesh as particularly vulnerable, alongside 36 others deemed at medium risk.

Understanding GLOFs

A GLOF occurs when water from a glacial or high-altitude lake is abruptly released, typically due to the failure of a natural dam formed by moraine. This sudden surge can transport vast amounts of rocks, sediment, and debris downstream, leading to widespread destruction.

Study Findings

The research, published in Discover Hazards, evaluated 127 lakes in Arunachal Pradesh, categorizing 89 as low risk, 36 as medium risk, and two as high risk. The lakes at medium and high risk are primarily located in Upper Dibang Valley, West Kameng, and Tawang, regions crucial for both local communities and hydropower projects.

Increasing Risks Due to Climate Change

Researchers cautioned that as glaciers recede and high-altitude lakes grow due to rising temperatures, the risk of GLOFs is likely to escalate. The study noted that many rivers originating from these high-altitude areas feed into the Brahmaputra river, indicating that even a minor GLOF could have significant downstream impacts, exacerbating flooding through sediment accumulation and instability in river channels.

Lake Expansion Observed

Utilizing satellite data from multiple time periods, the study revealed a notable increase in both the number and size of lakes in Arunachal Pradesh from 1988 to 2020. The state saw its lake count rise from 1,487 to 1,985, with the total area expanding from 7,921.95 hectares to 11,134.51 hectares.

Trends Among Glacial Lakes

Interestingly, the study found varying trends among different types of glacial lakes. Proglacial lakes (PGLs), which are directly adjacent to glaciers, experienced a slight decrease in number but an increase in area. In contrast, unconnected glacial lakes (UGLs) saw their numbers rise while their total area diminished.

Climate Change Implications

The researchers employed the Analytic Hierarchy Process (AHP) to assess GLOF risks, identifying lake expansion and proximity to glaciers as key factors. Previous studies have linked the proliferation of glacial lakes to climate change, with rising temperatures accelerating glacier melt and lake formation.

Need for Monitoring and Preparedness

The study emphasizes the necessity for ongoing monitoring, updated hazard assessments, and enhanced preparedness strategies, including early-warning systems and community education initiatives to safeguard critical infrastructure.

Risk Assessment and Future Considerations

Nepal-like devastation unlikely, but risk remains

Nabajit Hazarika from Cotton University, one of the researchers, indicated that while a disaster similar to that in Nepal is improbable in Arunachal Pradesh due to the distance of settlements from high-risk lakes, the potential impact of a GLOF should not be underestimated. The severity of a GLOF can vary based on how far water and debris travel downstream.

Hazarika also noted that this assessment should be viewed as an estimate, as there may be other hazardous lakes yet to be evaluated.