Published on 23 Feb 2025
Glacial Lakes-, are large bodies of water that sit in front or on top or beneath a melting glacier. As the glacial lakes grow larger, they become more dangerous because they are dammed by unstable ice or sediments composed of loose rock and debris. When the boundary around these glacial lakes breaks, huge amounts of water rush down the side of the mountains, which causes flooding in the downstream areas. This is called glacial lake outburst floods or GLOF.
Some Examples of GLOF in India are
Uttarakhand Kedarnath Flash Flood 2013 induced by GLOF in the Chorabari Tal glacial lake,
GLOF in Uttarakhand Chamoli District in the Nanda Devi Glacier.
GLOF event from South Lhonak Lake in northwest Sikkim.in 2023
Reasons for GLOFs
Melting Glaciers: Rising temperatures cause rapid melt, increasing water pressure on unstable lake boundaries (ice, debris), leading to breaches and floods.
Landslides/Earthquakes: These events displace large water volumes in glacial lakes, breaching natural dams and triggering GLOFs.
Extreme Weather: Heavy rain, storms, and sudden temperature changes can destabilize glacial lakes and contribute to GLOFs.
Climate Change: Accelerated glacial melt creates more lakes and increases extreme weather events, both raising GLOF risk (especially in the Hindu Kush-Himalayas).
Volcanic Activity: Eruptions near glaciers can trigger GLOFs by causing rapid melting.
Moraine Weakness: Moraines (natural dams) can weaken and breach, releasing the dammed water in a GLOF.
Human Activities: Infrastructure projects (dams, roads) in mountains can intensify geological stresses, potentially leading to GLOFs (e.g., 2021 Chamoli disaster).
Measures to mitigate GLOF disasters
Identify Risky Lakes: NDMA guidelines call for identifying potentially dangerous lakes based on observations, past events, and geological characteristics. This helps plan development around them.
Technology Intervention: Promote Synthetic-Aperture Radar (SAR) imagery to automatically detect changes in water bodies, including new lake formations during monsoons.
Reduce Lake Volume: Implement controlled breaching, pumping, or tunnelling to reduce water volume in critical glacial lakes.
Strengthen Early Warning Systems (EWS): Increase the number of deployed EWS across the Himalayas for effective mitigation.
Upgrade Alarming Systems: Complement traditional acoustic alarms with modern communication technology like smartphone alerts to facilitate early evacuation.
Regulate Construction: Develop uniform construction codes for infrastructure and excavation activities in vulnerable zones.
Land-Use Planning: Establish land-use planning procedures for areas prone to GLOFs.
Train Local Communities: Train local communities along with specialized forces like NDRF and ITBP. Research shows that local communities perform over 80% of initial search and rescue before professional intervention.
Geography
GLACIAL LAKE OUTBURST FLOOD
GLOF
Some Examples of GLOF in India
Reasons for GLOFs
Vulnerability of Himalayas to GLOFs
Measures to mitigate GLOF disasters
General Studies Paper 1
Natural Calamities and Disaster Management