Why in News: GLOF events in Nepal on July 8 2025 have highlighted the urgent need for transboundary early warning systems and enhanced regional cooperation to address rising GLOF risks in the Himalayas.
Glacial Lakes:
- Water bodies formed by melting glaciers, usually in basins carved by glacial movement.
Glacial Lake Outburst Floods (GLOFs):
- Sudden release of meltwater from glacial lakes due to failure of moraine or ice dams, causing flash floods.
Nature of GLOF Risk in India:
- India’s Himalayan Region has 28,000 glacial lakes, with 7,500+ above 4,500 m, making access and monitoring difficult.
- Rising temperatures have increased glacial melt and GLOF risks.
Major incidents include:
- Chorabari GLOF (2013) – Kedarnath disaster.
- South Lhonak GLOF (2023) – Damaged Chungthang Dam in Sikkim.
Prominent Types of Glacial Lakes in IHR:
- Supraglacial Lakes: Formed on glacier surfaces; prone to rapid summer melting.
- Moraine-dammed Lakes: Located at glacier snouts, held by debris/ice; prone to sudden breaches.
Major Causes of GLOFs:
- Glacial Surging: Sudden glacier movement causing rapid melt (e.g., Gilkey Glacier, Alaska).
- Moraine Dam Instability: Collapse of weak debris dams (e.g., South Lhonak GLOF, Sikkim).
- Ice Dam Failure: Weakening due to heat, water pressure, and internal melting.
- Seismic Activity: Earthquakes triggering dam or slope failure.
- Human Activity: Urbanization, deforestation, mining, hydropower, and GHG emissions destabilizing slopes and drainage
India’s Preparation Against GLOF Events
A. Policy & Institutional Response:
- Led by NDMA under CoDRR, shifting focus to risk reduction.
- Launched $20 million programme targeting 195 high-risk lakes, categorized into 4 risk levels.
B. Key Objectives of the programme :
1. Hazard assessment
2. Install AWWS
3. Set up Early Warning Systems
4. Water drawdown/retention structures
5. Community engagement
C. Scientific & Technological Measures:
- SAR Interferometry for slope monitoring
- Bathymetry, ERT, UAV surveys, remote sensing for lake monitoring
D. Monitoring Systems:
- Two Sikkim lakes have real-time monitoring:
- Data every 10 mins + daily photos
E. Manual Early Warning:
- ITBP assigned manual alert duties in high-altitude regions.
Challenges in Managing GLOFs:
- Inaccessible Terrain: Difficult Himalayan conditions hinder regular monitoring.
- Lack of Early Warning Systems: EWS requires robust planning and costly infrastructure.
- High Vulnerability: Region lies in seismic zones IV & V, prone to quakes and landslides.
- Climate Change Impact: Rising temperatures accelerating glacier melt.
- Severe Future Risk: ICIMOD warns 70–80% of glaciers in Hindu Kush Himalaya may vanish by 2100 under high emissions.
Recent GLOF Events in Nepal:
- July 8, 2025 – Lende River: Supra-glacial lake burst in Tibet; flash flood destroyed China-built bridge in Nepal.
- July 8, 2025 – Mustang: Moraine-dammed lake burst causing second GLOF.
- May 2025 – Humla: Two glacial lake bursts reported.
Challenges in Trans-Boundary Early Warning:
- No formal EWS between China and Nepal.
- China did not alert Nepal about the July 8, 2025 GLOF.
- Trans-boundary watersheds (e.g., Tibet to Nepal) hinder timely warnings and joint response.
Way Forward for Managing GLOF Risks in India
- Comprehensive Understanding: Deepen knowledge of GLOF causes, triggers, and processes using scientific research and case studies from the Himalayas and other mountain ranges (Alps, Andes, Tian Shan).
- Collaboration & Strategy Development: Foster multi-stakeholder cooperation among scientists, policymakers, technology innovators, and local communities to design and implement effective GLOF monitoring and mitigation strategies.
- Mitigation Approaches: Implement both structural (controlled breaching, siphoning, outlet control structures) and non-structural measures with active community participation.
- Advanced Monitoring & Early Warning: Integrate satellite-based monitoring, GIS, remote sensing, and SAR interferometry and Develop tailored early warning systems suited to the Himalayan terrain.
- Programme Scaling: Expand the national GLOF risk reduction programme leveraging funds from the 16th Finance Commission (FY2027–31).
- Infrastructure & Technology: Address gaps by deploying more on-ground weather stations and involving Indian technological expertise.
- Community Engagement: Increase awareness and participation of local populations in risk reduction efforts.
- Transboundary Cooperation: Strengthen coordination with neighboring countries, especially China and Nepal, for real-time early warnings and joint disaster response
UPSC RELEVANCE
GS Paper 1 (Geography)
- Physical geography: Glacial processes, Himalayan ecosystem, river basins, and climate change impact on glaciers.
- Disaster geography: Natural hazards, causes, and effects of GLOFs.
GS Paper 3 (Science & Technology, Environment, Economy)
- Use of remote sensing, GIS, satellite imagery, SAR interferometry in disaster prediction.
UPSC Mains Practice Question
Q. “Glacial Lake Outburst Floods (GLOFs) pose a significant threat to the Indian Himalayan Region. Examine the causes and consequences of GLOFs and discuss India’s approach towards their mitigation and management.”