Why in the News?
An ISRO study found that the 2025 Dharali flash flood in Uttarakhand was caused by the sudden collapse of an exposed ice patch in the Srikanta Glacier's nivation zone, not a cloudburst or Glacial Lake Outburst Flood (GLOF).
More in the News
- The study, titled 'Ice-patch collapse and early-warning implications from a Himalayan flash flood: emerging cryo-hydrological hazards under deglaciation', concludes that the collapse of an ice patch on the glacier above Dharali is linked to deglaciation in the Himalaya.
- The findings expand the range of recognised glacier-related hazards in the Himalaya and identify exposed ice patches as an under-recognised risk from glacier melt.
- Nivation is defined as the erosion of the ground beneath and around a snow bank, primarily as a result of alternate freezing and thawing.
Factors Contributing to Melting of Glaciers
- Global Warming and Climate Change: The primary driver of glacier retreat, thinning, and mass loss is the steady rise in regional and global temperatures caused by climate change.
- Black Carbon and Surface Debris: The accumulation of englacial or supra-glacial debris and black carbon on the ice surface absorbs heat and heavily induces glacial melt.
- Elevation-Dependent Warming: Higher altitudes (4,500–6,000 meters) are warming faster than lower regions, exposing most glacier zones to intensified and rapid temperature rise.
- Loss of Insulating Snow Cover: Decline in seasonal snow and firn weakens natural insulation, making underlying ice more prone to fragmentation and faster melting.
- Erratic Weather Systems: Changing climatic patterns, such as increasingly erratic Western Disturbances, are reducing core winter snowfall and shifting precipitation seasonality.
- Steep Topography: Steep longitudinal gradients (exceeding 35°–40°) and narrow valley confinements act as catalysts, transforming minor upstream ice collapses into high-velocity, highly destructive debris surges.
Effects of Deglaciation in the Himalayas
- Glacial Lake Outburst Floods (GLOFs): Retreating glaciers leave behind meltwater that forms lakes dammed by unstable moraines (debris and ice).
- These can breach due to avalanches, earthquakes, or rockfalls, releasing millions of cubic meters of water and debris catastrophically.
- Cascading Disasters: Deglaciation destabilizes thermal and hydrological systems, triggering interconnected hazards like permafrost thaw, landslides, debris flows, and rock-ice avalanches
The ICIMOD Report (Hindu Kush Himalaya Glacier Melting)
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- Water Insecurity: Shrinking glaciers disrupt sustained meltwater supply, leading to reduced river flows, altered hydrology, and long-term water scarcity affecting millions dependent on Himalayan rivers.
- Agricultural & Ecological Disruption: Warmer winters are causing crops (like apples and cherries) to miss vital chilling requirements, resulting in poor yields, earlier outbreaks of pests, and disrupted local ecosystems.
- Socio-Economic and Infrastructure Destruction: Flash floods and debris flows damage settlements, farmland, roads, bridges, tourism, and hydropower infrastructure.
Disaster Management
- Institutional Framework & Government Initiatives
- Nodal Agencies: The Ministry of Jal Shakti (MoJS) and the Central Water Commission (CWC) act as the nodal bodies for managing glacial studies and GLOF hazards.
- National GLOF Risk Mitigation Programme (NGRMP): A dedicated NDMA initiative (Phase-1 from 2023-2026) targeting high-risk states/UTs: Himachal Pradesh, Uttarakhand, Sikkim, Arunachal Pradesh, J&K, and Ladakh.
- Disaster Preparedness & Mitigation Strategies
- Satellite-Based Early Warning: Detecting exposed ice patches using multi-temporal Earth observation imagery (like Sentinel-2) should be integrated into operational early-warning systems to identify high-risk areas before they collapse.
- Multi-Risk Assessment: Integrating hazard models with vulnerability assessments (population, infrastructure, hydrology) to create GIS-based, multi-hazard risk maps.
- Community-Centric Monitoring: Train local communities, porters, and shepherds to report early warning signs like river turbidity or cracks using mobile-based citizen science platforms.
- Bio-Restoration: Promote moss/algae growth to reduce melting and plant vegetation to stabilize moraines and prevent erosion.
- Structural Mitigation Measures (Geo-Engineering): Reduce glacial lake risks through controlled drainage, siphoning, or tunnelling.
- Robust Watershed Management: Expanding initiatives like the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY-WDC) to build check dams, percolation tanks, and farm ponds to enhance groundwater recharge.
- Integrated Preparedness Policies: Ensure coordination across sectors with both short-term contingency and long-term climate strategies.
Conclusion
The rapid retreat of the "Third Pole" is not a distant warning but an immediate reality threatening the water, food, and energy security of billions. Addressing this requires transboundary cooperation, mainstreaming disaster risk reduction in development, and empowering local institutions. India must integrate advanced geospatial monitoring with community-based adaptation strategies to effectively manage rising cryo-hydrological risks.
