Assessment of Hazardous Glacial Lakes

Assessment of Hazardous Glacial Lakes


In the news

The Uttarakhand government has taken proactive measures by forming two expert teams to evaluate the risk associated with five potentially hazardous glacial lakes in the region.

Key Points related to Glacial Lakes

  • Prone to GLOFs
    • These glacial lakes are susceptible to Glacial Lake Outburst Floods (GLOFs), which have caused significant disasters in the Himalayan states in recent years.
    • GLOFs occur when the natural dams that contain glacial lakes are breached, releasing large volumes of water downstream.

  • Objective of Risk Assessment
    • The primary objective of this exercise is to assess and mitigate the risk of GLOF incidents.
    • By identifying potential hazards and vulnerabilities, authorities aim to minimize the impact of a GLOF event and provide sufficient time for relief and evacuation efforts.
  • Involvement of NDMA
    • The National Disaster Management Authority (NDMA), operating under the Union Ministry of Home Affairs, has identified 188 glacial lakes in the Himalayan states that pose a risk of breaching due to heavy rainfall.
    • Among these, thirteen hazardous glacial lakes have been identified in Uttarakhand alone, highlighting the urgent need for risk evaluation and mitigation measures.
  • Risk Mitigation Strategies
    • The assessment conducted by expert teams will likely involve various strategies to reduce the vulnerability of communities living downstream of these glacial lakes.
    • Possible measures may include early warning systems, construction of protective structures, and land use planning to minimize exposure to flood risks.
  • Collaborative Efforts
    • The initiative underscores the importance of collaboration between state and national agencies, as well as scientific experts, to address the complex challenges posed by climate change and glacial lake hazards.
    • Effective coordination and communication among stakeholders are essential for implementing proactive measures and enhancing the resilience of vulnerable communities.
  • Long-Term Planning
    • Assessing and mitigating the risk associated with hazardous glacial lakes is part of a broader strategy for disaster risk reduction and climate change adaptation in the Himalayan region.
    • Long-term planning efforts should prioritize sustainable development practices and ecosystem conservation to minimize the impact of natural hazards on local communities and ecosystems.
  • Public Awareness and Preparedness
    •  Alongside technical assessments and infrastructure development, raising public awareness about GLOFs and disaster preparedness is crucial.
    •  Educating communities about evacuation procedures, emergency shelters, and early warning systems can help reduce casualties and enhance resilience in the face of natural disasters.

About the Glacial Lake Outburst Floods (GLOFs)

Rising global temperatures, including in India, have amplified the threat of Glacial Lake Outburst Floods (GLOFs), endangering millions of people worldwide.

GLOFs are catastrophic events triggered by the sudden release of water from glacial lakes, posing grave risks to communities downstream.

What are GLOFs?

  • GLOFs occur when water stored in glacial lakes, formed by the melting of glaciers, is rapidly discharged due to natural or human-induced factors.
  • These lakes form as glaciers retreat, leaving depressions that fill with meltwater, creating unstable reservoirs held back by ice or loose debris.
  • When the natural barriers restraining the water fail, a surge of water cascades down mountainsides, inundating downstream areas in what is known as a GLOF event.

Causes of GLOFs

  • Glacial calving, where ice breaks off glaciers and falls into the lake, can trigger GLOFs by displacing large volumes of water.
  • Additionally, events like avalanches or landslides can destabilize the boundaries of glacial lakes, leading to breaches and sudden water release.

Impact of GLOFs

  • GLOFs unleash torrents of water, sediment, and debris downstream at high speeds, causing widespread devastation.
  • Valleys and settlements in the path of GLOFs are submerged, while critical infrastructure such as roads, bridges, and buildings are destroyed.
  • The aftermath of GLOFs often results in significant loss of life, displacement of communities, and disruption of livelihoods, exacerbating the socio-economic impact.

Rising significance of GLOFs 

  • Recent Surge in GLOF Events
    • Global temperatures have surged, accelerating glacier melting and leading to a rise in Glacial Lake Outburst Floods (GLOFs) in the Himalayan region.
    • Rapid infrastructure development in vulnerable areas has further exacerbated the frequency and intensity of GLOF incidents.
  • Research Findings
    • A study published in the journal Nature in 2023 highlighted the alarming increase in GLOFs in the Himalayan region since 1980. Conducted by experts from the Institute of Tibetan Plateau Research in China, the analysis revealed that approximately 6,353 square kilometers of land are at risk from potential GLOFs. This poses threats to various vital infrastructure, including buildings, hydropower projects, farmland, roads, and bridges.
    • Another study, also published in Nature in February 2023, underscored the widespread risk of GLOFs in India and Pakistan. Researchers from leading universities in the United Kingdom and New Zealand found that about 3 million people in India and 2 million in Pakistan face the threat of GLOFs. Despite not having the largest number or size of glacial lakes, the densely populated and vulnerable nature of these regions elevates their GLOF risk globally.
  • High Vulnerability in India and Pakistan
    • While the number and size of glacial lakes in India and Pakistan may not be as significant as in other regions, such as the Pacific Northwest or Tibet, the densely populated areas and their susceptibility to GLOFs make them among the most at-risk globally.
    • According to experts, the large population coupled with high vulnerability amplifies the danger posed by GLOFs in India and Pakistan, necessitating urgent attention and mitigation measures.

Situation in Uttarakhand

  • Past GLOF Events
    • Uttarakhand has experienced two significant Glacial Lake Outburst Flood (GLOF) events in recent years. The first occurred in June 2013, devastating large parts of the state, with the Kedarnath valley bearing the brunt of the disaster, resulting in thousands of casualties. The second event struck Chamoli district in February 2021, causing flash floods due to the bursting of a glacier lake.
  • Classification of Glacial Lakes
    • Uttarakhand is home to 13 glacial lakes categorized based on their risk levels into three categories 'A', 'B', and 'C'. Among these, five highly sensitive lakes fall under the 'A' category. 
    • Notable lakes include Vasudhara Tal in the Dhauliganga basin, and lakes in Pithoragarh district such as Maban Lake, Pyungru Lake, and two unclassified lakes. These lakes, ranging from 0.02 to 0.50 sq km in area and situated at elevations between 4,351 to 4,868 meters, are at high risk of GLOFs.
  • Impact of Rising Temperatures
    • The increasing surface temperatures pose additional challenges for Uttarakhand. A 2021 study by the Potsdam Institute for Climate Research (PIK) and The Energy and Resources Institute (TERI) predicts a rise in the hill state's annual average maximum temperature by 1.6-1.9 degrees Celsius between 2021-2050. This elevation in temperature could heighten the vulnerability to GLOFs in Uttarakhand.

Government Initiatives

  • National Glacial Lake Outburst Floods Risk Mitigation Programme (NGRMP)
    • The Indian government initiated a ₹150 crore program to mitigate risks associated with glacial lakes in the Himalayan region.
    • The NGRMP action plan includes four key components aimed at addressing various aspects of Glacial Lake Outburst Floods (GLOFs).
  • Component 1 GLOF Hazard and Risk Assessment (15% of Budget)
    • Focuses on creating and updating a glacial lake inventory.
    • Classification based on hazard, vulnerability, and risk assessment.
  • Component 2 GLOF Monitoring and Early Warning System (35% of Budget)
    • Emphasizes the implementation of monitoring systems using remote sensing techniques, advanced seismometers, water level sensors, and cameras.
    • Development of a warning system with smartphone alerts and sirens to prevent loss of life and property downstream.
  • Component 3 GLOF Mitigation Measures (40% of Budget)
    • Allocates funds for site-specific interventions such as reinforcing unsafe moraine dams, draining lake waters through siphoning, controlled blasting, and excavation of artificial drainage channels.
  • Component 4 Awareness Generation and Capacity Building (Remaining Budget)
    • Focuses on community-centric capacity building and awareness generation involving various stakeholders.
    • Aims to prepare contingency plans and promote research and development on glacial recession and GLOFs.
  • NDMA Guidelines
    • The guidelines of the National Disaster Management Authority (NDMA) will assist Central Ministries, Departments, and States in formulating disaster management plans.
    • Collaboration and cooperation with NDMA will be essential for carrying out the mandate effectively.

Way Forward

  • Integrated Efforts
    • Collaboration and cooperation among various institutions are imperative to effectively address the risk posed by Glacial Lake Outburst Floods (GLOFs).
    • Joint efforts can ensure a coordinated approach towards risk assessment, mitigation, and response strategies.
  • Comprehensive GLOF Risk Mitigation Plan
    • Prioritize the development and implementation of a comprehensive GLOF risk mitigation plan.
    • Installation of monitoring and early warning systems should be a key component of this plan to enhance preparedness and response capabilities.
    • Early Warning Systems (EWS) are crucial for timely evacuation and minimizing the impact of GLOFs on vulnerable communities.
  • Use of Technology as a Mitigating Tool
    • Leverage technology for monitoring, reducing the impact, and post-flood rehabilitation.
    • Implement advanced monitoring systems, satellite imagery, and data analytics to track glacier movements, lake levels, and potential risks.
    • Utilize drones and GIS mapping for accurate risk assessment and disaster management strategies.
  • Revised Safety Standards
    • Review and update safety standards for infrastructure and construction projects in mountainous and river areas.
    • Ensure strict adherence to regulations to mitigate risks associated with GLOFs and safeguard lives and property.
  • Scientific Research
  • Scale up scientific research on glaciers in the country to enhance understanding and prediction of glacial behavior.
  • Invest in studies focusing on glacier dynamics, climate change impacts, and GLOF risk assessment to inform evidence-based policy decisions and mitigation strategies.


Addressing the risks associated with Glacial Lake Outburst Floods (GLOFs) requires a multifaceted approach. Collaboration among government agencies, scientific institutions, and local communities is essential for a coordinated effort. Prioritising the development of a comprehensive GLOF risk mitigation plan, including the installation of monitoring and early warning systems, is crucial. Leveraging technology such as advanced monitoring systems, satellite imagery, drones, and GIS mapping can provide valuable data for accurate risk assessment and disaster management strategies. It's imperative to review and update safety standards for infrastructure projects and invest in scientific research on glaciers to inform evidence-based policy decisions. By implementing these solutions, we can mitigate the risks of GLOFs and enhance the resilience of vulnerable communities.


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