IN NEWS

India Strengthens Preparedness Against Glacial Lake Outburst Floods (GLOFs) in Himalayan Region

ANALYSIS

8India is intensifying its efforts to monitor and mitigate the growing threat of Glacial Lake Outburst Floods (GLOFs) in the Himalayan region amid rising temperatures, accelerated glacial melt and increasing climate vulnerability. The issue gained renewed attention following catastrophic GLOF events in Nepal in July 2025, which damaged hydropower infrastructure, washed away bridges and caused major downstream flooding. (thehindu.com)The increasing frequency of such events has highlighted the urgent need for:

• Early warning systems
• Scientific monitoring
• Cross-border coordination
• Climate adaptation measures

What are Glacial Lake Outburst Floods (GLOFs)?

A Glacial Lake Outburst Flood (GLOF) occurs when water stored in a glacial lake is suddenly released due to the failure of natural barriers such as moraine dams or ice barriers.The sudden discharge generates:

• Flash floods
• Debris flows
• Landslides
• Downstream destruction

GLOFs are particularly dangerous in the Himalayas because of:

• Steep terrain
• Fragile geology
• Rapid glacial retreat
• Dense downstream settlements and hydropower infrastructure

Types of Glacial Lakes in Indian Himalayan Region (IHR)

According to India’s National Remote Sensing Centre (NRSC), the Indian Himalayan Region contains nearly 28,000 glacial lakes across 11 river basins.The article highlights two major types of glacial lakes:

1. Supraglacial Lakes

6These lakes form:

• On the surface of glaciers
• In depressions created by melting ice

Characteristics:

• Highly vulnerable to summer melting
• Rapidly expand during rising temperatures
• Common in glacier-ablation zones

2. Moraine-Dammed Lakes

8These lakes form:

• At the snout or toe of glaciers
• Water is retained by loose moraine debris or buried ice cores

Characteristics:

• Highly unstable
• Vulnerable to sudden dam failure
• Sensitive to landslides and avalanches

Most catastrophic GLOFs originate from moraine-dammed lakes.

Increasing GLOF Risk in Himalayas

Climate Change and Glacial Melt

The article notes that:

• 2023 and 2024 were among the hottest years globally
• Rising temperatures accelerated glacial melt in the Himalayas

This has caused:

• Expansion of glacial lakes
• Weakening of moraine dams
• Increased hydrostatic pressure
• Greater flood vulnerability

Triggering Factors

Nearly:

• Two-thirds of GLOFsare triggered by:
  • Ice avalanches
  • Landslides

The remaining are caused by:

• Excessive meltwater pressure
• Earthquakes
• Moraine dam failure

Major GLOF Events Mentioned

Nepal GLOF Events (2025)

In July 2025:

• A supra-glacial lake burst in Tibet triggered flooding in Nepal.
• The event damaged:
  • China-built friendship bridge
  • Rasuwagadhi inland port
  • Hydropower infrastructure

Additional GLOF events occurred in:

• Mustang district
• Humla district

South Lhonak GLOF, Sikkim (2023)

5One of India’s most destructive recent GLOFs.Impact included:

• Destruction of the 1250 MW Chungthang dam
• Severe flooding in Teesta basin
• Massive silting downstream
• Reduction in river carrying capacity

Chorabari GLOF (Kedarnath Disaster, 2013)

The Chorabari glacial lake burst, combined with:

• Cloudbursts
• Landslides

resulted in the catastrophic Kedarnath disaster, causing:

• Heavy casualties
• Infrastructure destruction
• Major environmental damage

India’s Mitigation Strategy

NDMA’s National Programme

The National Disaster Management Authority (NDMA) has shifted focus from post-disaster response to proactive risk reduction.Key developments include:

The programme is expected to expand further after the recommendations of the 16th Finance Commission.

Major Components of GLOF Risk Reduction

1. Hazard Assessment

Scientific assessment of:

• Lake stability
• Water volume
• Moraine structure
• Slope vulnerability

2. Automated Weather and Water Stations (AWWS)

Monitoring stations now transmit:

• Weather data
• Water-level information
• Lake imagery every 10 minutes

3. Early Warning Systems (EWS)

Downstream alert systems are being developed for:

• Flood forecasting
• Community evacuation
• Disaster response

4. Engineering Mitigation

Methods include:

• Artificial channels for water release
• Flow retention structures
• Controlled lowering of lake levels

5. Community Engagement

Local participation is essential because:

• Himalayan communities possess traditional ecological knowledge
• Sacred lakes require cultural sensitivity
• Community trust improves monitoring effectiveness

Scientific Technologies Used

SAR Interferometry

4The programme promotes use of:

• Synthetic Aperture Radar (SAR) Interferometry

This technology helps detect:

• Micro-changes in slope stability
• Surface deformation
• Landslide risk

using satellite imagery.

Other Technologies Mentioned

Importance of Transboundary Cooperation

The article stresses the need for coordination between:

• India
• Nepal
• China

because many Himalayan watersheds are transboundary.Absence of real-time information sharing can delay:

• Early warnings
• Disaster response
• Hydrological coordination

STATIC PART

National Disaster Management Authority (NDMA)

Indian Himalayan Region (IHR)

Important Terms

Updated – 29 July 2025 ; 01:47 PM |The Hindu News Source