"Himalayan Glacier Collapse Triggers Nepal Floods, Exposing Regional Preparedness Gaps"
Glacial Lake Outburst Flood (GLOF)
sudden failure of an ice/moraine dam releasing catastrophic water and debris downstream
Glacial Detachment
entire ice mass separating from bedrock, mobilising as fast-moving ice-rock-water slurry
The Hindu Kush Himalayan (HKH) region spans eight countries and contains over 54,000 glaciers, making it the largest glaciated area outside the polar zones. Often called the Water Tower of Asia, its glaciers feed the Indus, Ganga, and Brahmaputra river systems, sustaining hundreds of millions of people through drinking water, irrigation, and hydropower. The region is also among the most geologically young and seismically active on Earth, making it inherently prone to landslides, avalanches, and flash floods. Rivers like the Trishuli, Bhotekoshi, Koshi, Gandak, and Bagmati originate in the Tibetan Plateau, descend steeply through Nepal, and enter India's northern plains — meaning disasters upstream carry direct downstream consequences for Indian states like Bihar, Uttar Pradesh, Assam, and West Bengal.
India's disaster governance rests on the Disaster Management Act, 2005, which established a three-tier structure: the National Disaster Management Authority (NDMA) at the apex, State Disaster Management Authorities (SDMAs), and District Disaster Management Authorities (DDMAs). Both India and Nepal are signatories to the Sendai Framework for Disaster Risk Reduction 2015–2030, whose Target G calls for universal access to multi-hazard early warning systems by 2030. The Rashtriya Barh Ayog (National Flood Commission) has identified approximately 40 million hectares of Indian land as flood-prone. Despite these frameworks, real-time hydrological data sharing among India, Nepal, and China — the three countries sharing the upper Himalayan watershed — remains critically underdeveloped, and a nationally operationalised early warning system for Himalayan glacial hazards does not yet exist.
A Glacial Lake Outburst Flood (GLOF) occurs when a natural dam — formed by ice, moraine, or debris — holding back a high-altitude glacial lake fails suddenly. Triggers include ice-rock avalanches, intense rainfall, seismic shocks, or gradual weakening of the ice dam. A related phenomenon, the glacial detachment, involves an entire ice mass separating from its bedrock anchor and mobilising as a fast-moving slurry of ice, rock, and water — distinct from a conventional avalanche. Hanging glaciers, ice masses perched on steep slopes attached to the mountain face at only a few points, are especially prone to sudden detachment as warming reduces internal ice cohesion and thaws the permafrost anchoring them. The IPCC has consistently documented accelerating glacier retreat across the HKH region, and the International Centre for Integrated Mountain Development (ICIMOD) has documented a significant increase in glacial lake area in recent decades.
The Himalayan hazard cascade typically begins at high altitude and amplifies downstream. An ice-and-rock avalanche strikes a glacial lake, triggering an outburst; the resulting flood surge picks up sediment and debris, increasing its destructive mass as it travels down narrow valleys at high speed. …
Differentiate the causes of landslides in the Himalayan region and Western Ghats.
Consider the following pairs:
Glacier — River
1.Bandarpunch — Yamuna
2.Bara Shigri — Chenab
3.Milam — Mandakini
4.Siachen — Nubra
5.Zemu — Manas
Which of the pairs given above are correctly matched?
Consider the following pairs:
Peak — Mountains
1.Namcha Barwa — Garhwal Himalaya
2.Nanda Devi — Kumaon Himalaya
3.Nokrek — Sikkim Himalaya
Which of the pairs given above is/are correctly matched?
Siachen Glacier is situated to the
Consider the following statements regarding glacial hazards in the Himalayan region:
1.A Glacial Lake Outburst Flood (GLOF) occurs when a moraine dam holding back a glacial lake fails suddenly.
2.Hanging glaciers are ice masses that flow along valley floors and are grounded along their full length.
3.A 2021 multi-institution study flagged the instability of South Lhonak Lake in Sikkim before it burst in 2023.
4.The Bhote Koshi River originates near the Nepal-China border.
How many of the above statements are correct?
Consider the following pairs:
Glacier/Lake — Location/River
1.South Lhonak Lake — Sikkim
2.Siachen Glacier — Nubra River
3.Bara Shigri Glacier — Chenab River
4.Zemu Glacier — Manas River
How many of the above pairs are correctly matched?
With reference to the Alaknanda basin in the Garhwal Himalayas, consider the following statements:
1.A recent study identified 219 hanging glaciers in the basin, covering approximately 71.7 sq km.
2.Infrastructure at risk from glacial avalanche hazard in the basin is projected to increase by 120% by 2030 compared to 2000.
3.The Alaknanda River is a tributary of the Yamuna River system.
Which of the statements given above is/are correct?
Which of the following best explains why the early-warning system on the Bhote Koshi River failed to detect the recent glacial disaster in Nepal?
Assertion (A): The 2025 Blatten glacier collapse in Switzerland resulted in far fewer casualties than comparable Himalayan glacial disasters despite similar scale.
Reason (R): The Alps and the Himalayas have identical geological structures, making Swiss monitoring techniques directly transferable to India.
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