Why in NEWS

Frequent Glacial Lake Outburst Floods (GLOFs) in Nepal have raised alarm in India’s Himalayan states, where over 7,500 glacial lakes—many unstable—pose a growing threat from climate change-driven disasters.

Key Terms and Concepts

Term	Explanation
GLOF	Sudden release of water from glacial lakes due to dam failure (ice/moraine), often catastrophic
Moraine	Accumulated rock and debris left by a glacier, often forms weak natural dams
Supraglacial Lake	Water body formed on glacier surface due to melting
SAR Interferometry	Satellite-based radar tech to detect terrain changes and slope shifts
AWWS	Automated Weather and Water Stations for real-time lake and weather monitoring

What Causes GLOFs?

Cause	Example
Climate Change	Melting glaciers form new, unstable lakes (e.g. 2013 Kedarnath tragedy)
Cloudbursts	Intense rainfall stresses moraine dams (e.g. 2023 North Sikkim GLOF)
Avalanches/Landslides	Trigger displacement waves breaching lake dams (e.g. 2021 Chamoli)
Earthquakes	Nepal 2015 quake altered lake stability
Weak Moraines	Piping erosion weakens moraine dams (e.g. 1985 Dig Tsho GLOF, Nepal)
Infrastructure Stress	Roads, dams worsen ecological fragility (e.g. Teesta-III Dam collapse in 2023)

Types of Himalayan Glacial Lakes

Type	Characteristics
Supraglacial	Formed on glacier surfaces; vulnerable to melt and collapse
Moraine-Dammed	Formed at glacier snouts, held by weak debris; most prone to GLOFs

India’s Vulnerability to GLOFs

Aspect	Details
Geographic Exposure	28,000+ glacial lakes in IHR; 7,500 in India, mostly >4500m elevation
Monitoring Challenges	Remote terrain restricts surveys; heavy reliance on satellite data
Risk Evidence	ISRO (1984–2023) reports 601 lakes have doubled in size since 2016
Past Disasters	2013 Kedarnath, 2021 Chamoli, 2023 Sikkim GLOFs caused deaths and infrastructure collapse
Lack of Early Warning	Inadequate on-ground systems; delayed detection increases disaster impact

Recent Measures by India

Initiative	Description
NDMA’s GLOF Mitigation Plan	$20 million plan for 195 high-risk lakes; focuses on pre-disaster readiness
Technological Tools	UAVs, ERT, bathymetry, SAR to map risk; AWWS in Sikkim for real-time alerts
Local & Security Forces	ITBP trained for manual alerts in remote zones; locals involved in awareness drives
NDMA’s 5-Fold Strategy	Includes hazard assessment, AWWS, EWS, mitigation (drawdowns), community outreach

Way Forward

Recommendation	Action Steps
Advance Monitoring	Expand AWWS, SAR, automated alerts, community-based warning systems
Strengthen Infrastructure	Enforce safety norms in dam design, promote GLOF-resilient hydropower
Leverage Indigenous Innovation	Fund local R&D for glacial safety; use spillways for lake drainage
Boost Governance	Mandate GLOF risk assessments, enable panchayat participation, hold joint drills with Nepal/China

In a Nutshell

Code: “MELT-R”
Moraine-dammed lakes growing
Earthquakes, avalanches trigger collapse
Lack of early warnings
Teesta, Kedarnath show human cost
Resilient systems needed now!

Prelims Practice Questions

1. Which of the following factors contribute to GLOF events?
   A. Cloudbursts
   B. Moraine dam failure
   C. Seismic activity
   D. All of the above
2. The South Lhonak GLOF (2023) led to the collapse of which major infrastructure project?
   A. Bhakra Nangal Dam
   B. Teesta-III Hydropower Project
   C. Nathpa Jhakri Plant
   D. Sardar Sarovar Dam
3. What is the role of AWWS in the context of GLOF mitigation?
   A. Construction of dams
   B. Glacier excavation
   C. Real-time lake and weather data monitoring
   D. Military communication

Mains Practice Questions

1. Discuss the rising threat of Glacial Lake Outburst Floods (GLOFs) in the Indian Himalayan Region and examine the adequacy of India’s preparedness. 10 Marks (GS3 – Disaster Management)
2. “GLOF management requires a synergy of science, policy, and community action.” Examine with examples from recent events. 10 Marks

Answers and Explanations (Prelims)

Qn	Answer	Explanation
1	D	All listed factors can trigger a GLOF
2	B	Teesta-III hydropower project was destroyed in the 2023 Sikkim GLOF
3	C	AWWS provide real-time lake and weather data to detect potential GLOFs early