India’s readiness for Glacial Lake Outburst Flood (GLOF) incidents

What is a Glacial Lake Outburst Flood (GLOF)?

It is the abrupt, disastrous outflow of water from a glacially created lake, typically obstructed by ice, debris, or bedrock.

They generate intense peak discharges that greatly surpass typical flood levels and can initiate damaging debris flows because of their strong erosion and transport capability.

Reasons

Moraine or Ice Dam Breakdown: Compromised structural strength resulting from thawing or seismic events.

Increasing temperatures have caused swift glacier melt, resulting in unstable lakes dammed by moraine.

Avalanches and landslides: Abrupt mass shifts into lakes can displace water and lead to dam collapse.

Seismic Events: Seismic Activity: Earthquakes may weaken moraine dams or initiate landslides.

Intense Rainfall and Cloudbursts: Surplus rainfall raises lake levels and stress on natural barriers.

Effects of GLOFs

Loss of Life and Livelihoods: Incidents such as the 2023 South Lhonak Lake breach in Sikkim resulted in the deaths of more than 100 individuals and forced thousands to relocate.

Infrastructure Damage: Bridges, roadways, and hydropower initiatives are extremely susceptible.

Environmental Deterioration: GLOFs wear down riverbanks, initiate landslides, and disturb ecosystems.

Financial Damage: Harm to power facilities, transportation systems, and farming results in prolonged economic challenges.

Circumstances in India

The Indian Himalayan Region (IHR), which contains 11 river basins and 28,000 glacial lakes, is increasingly endangered by glacial lake outburst floods (GLOFs), fueled by increasing global temperatures and intricate topography.

Two primary types of lakes—supraglacial and moraine-dammed—are especially at risk, as the majority of GLOFs are caused by ice avalanches, landslides, or pressure from meltwater.

Due to the presence of 7,500 lakes situated at elevations exceeding 4,500 metres, observation is restricted to remote sensing, which solely detects surface changes retroactively and provides minimal early warning.

At-risk downstream regions encounter significant threats to their infrastructure, ecosystems, and human lives, exemplified by the 2023 South Lhonak GLOF in Sikkim and the 2013 Kedarnath calamity.

Government Reaction

The Central Government has sanctioned the National Glacial Lake Outburst Flood (GLOF) Risk Mitigation Project (NGRMP) for execution in four states: Arunachal Pradesh, Himachal Pradesh, Sikkim, and Uttarakhand, with a budget of Rs.150.00 crore.

India, via the National Disaster Management Authority (NDMA), is transitioning from a post-disaster response strategy to a proactive approach for GLOF risk mitigation.

The Committee on Disaster Risk Reduction (CoDRR) collaborates with central agencies, research organizations, and States/UTs to oversee and reduce GLOF risks.

A national initiative was initiated, originally concentrating on 56 vulnerable glacial lakes, which has now grown to encompass 195, classified by risk level.

The programme has five main objectives: Evaluating the hazards of glacial lakes, Setting up Automated Weather and Water Stations (AWWS), Implementing Early Warning Systems (EWS) in downstream areas, Reducing risk through water management structures, and Engaging the community for preparedness and resilience.

Advancement

India’s efforts to mitigate GLOF have demonstrated encouraging advancements, with collaborative expeditions among various institutions in J&K, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh yielding positive results.

These teams performed bathymetric measurements, slope surveys, and Electrical Resistivity Tomography (ERT) to evaluate lake capacities and the stability of moraine dams.

Community involvement was vital, as local collaboration was key to achieving success.

Two lakes in Sikkim now have monitoring stations that offer real-time weather and water information.

Without automated systems, the Indo-Tibetan Border Police (ITBP) provides manual early warning support.

Additional monitoring systems and expeditions are scheduled after the monsoon to fill essential data gaps in the area.

Recommendations and Next Steps

Enhance Early Warning Systems and mobile broadcast notifications in at-risk areas.

Transboundary Collaboration: Work together with Nepal, Bhutan, and China for upstream surveillance.

Infrastructure Planning: Prevent essential facilities from being located downstream of lakes with high risk.

Climate Adaptation: Incorporate GLOF hazards into more extensive Himalayan climate resilience plans.