Study assesses risks from hanging glaciers in Central Himalaya

A new study published in the journal *npj Natural Hazards* (2026) identifies 219 hanging glaciers in the Alaknanda basin of Uttarakhand (Central Himalaya), c...

What Happened

A new study published in the journal npj Natural Hazards (2026) identifies 219 hanging glaciers in the Alaknanda basin of Uttarakhand (Central Himalaya), covering a total area of 71.7 ± 3.5 km² with an estimated ice volume of 2.39 ± 0.42 km³ — including 0.74 ± 0.14 km³ of hanging ice mass.
These hanging glaciers — which cling to steep slopes and cliffsides rather than occupying valley floors — are described as particularly sensitive to rising temperatures and shifting precipitation patterns, making them high-risk sources of sudden ice avalanches and glacial lake outburst floods (GLOFs).
The Alaknanda basin, a tributary of the Ganga, has already seen rapid glacial lake expansion: total glacial lake area in the basin grew from 0.748 km² (1990) to 2.538 km² (2020), a 239% increase over 30 years.
The study emphasises the downstream danger to densely populated river valleys, hydropower infrastructure, and pilgrimage routes in the region.

Static Topic Bridges

Glacial Lake Outburst Floods (GLOFs)

A Glacial Lake Outburst Flood (GLOF) is the sudden, large-scale release of water from a lake that has formed from glacial meltwater — typically dammed by a moraine (glacial debris ridge) or ice wall. When the natural dam is breached — due to ice melting, erosion, earthquake, or an ice/rock avalanche into the lake — a catastrophic flood surges downstream.

Hanging glaciers present a particular GLOF risk: they can break off suddenly (calve) due to warming, send ice-mass directly into downstream lakes, and trigger displacement waves that breach moraine dams. Unlike valley glaciers, hanging glaciers provide very little warning time.

Moraine-dammed lakes are the most common precursor to GLOFs in the Himalaya
Climate-driven glacier retreat is accelerating lake formation and expansion across the Hindu Kush-Himalaya (HKH) region
The Himalayan region has experienced warming of 0.23–0.52°C per decade — significantly above the global average
The Alaknanda and Dhauliganga sub-valleys contain 9 and 6 Potentially Dangerous Glacial Lakes (PDGLs) respectively — the highest concentrations in the basin
Glacial lake area in the Alaknanda basin grew by 239% between 1990 and 2020

Connection to this news: The 219 hanging glaciers identified in this study represent an elevated and poorly mapped GLOF trigger source. As these steep ice masses calve in response to warming, they can instantly generate floods and debris flows without the slower warning signals (lake expansion, moraine seepage) that precede conventional GLOFs.

Alaknanda Basin: Geography and Significance

The Alaknanda is one of the two principal headstreams of the Ganga (the other being the Bhagirathi). It originates near Satopanth Glacier in the Garhwal Himalaya of Uttarakhand and flows through the Chamoli district before joining the Bhagirathi at Devprayag to form the Ganga. The basin encompasses major pilgrimage sites (Badrinath, Kedarnath corridor), several hydropower projects, and dense human settlements in narrow gorges.

Alaknanda merges with Bhagirathi at Devprayag → Ganga (Panchprayag system)
Key tributaries: Dhauliganga, Nandakini, Pindar, Mandakini
The basin is geologically young (Himalayan orogeny) — steep slopes, loose rock, high seismicity (Seismic Zone IV/V)
Major hydropower infrastructure: Tapovan-Vishnugad and Tehri Dam system downstream
Located in: Chamoli, Rudraprayag, Pauri Garhwal districts of Uttarakhand

Connection to this news: The Alaknanda basin's combination of steep terrain, high GLOF risk glacial lakes, critical infrastructure, and pilgrimage density makes the findings of this study directly relevant to disaster preparedness planning.

Himalayan Glaciology and Climate Change

The Himalayan cryosphere — comprising approximately 9,600 glaciers covering about 16,600 km² in the Indian Himalaya — is undergoing accelerated retreat due to climate change. The Himalayan glaciers are often called the "Third Pole" (alongside the Arctic and Antarctic) due to their ice mass.

Hindu Kush-Himalaya (HKH) region glaciers supply water to 10 major river systems (Ganga, Brahmaputra, Indus, Mekong, Yangtze, etc.), serving ~1.9 billion people downstream
Himalayan warming is occurring at nearly double the global average rate
India's Himalayan glaciers are retreating at varying rates — some at 20–50 metres per year
The Geological Survey of India (GSI) and National Centre for Polar and Ocean Research (NCPOR) under Ministry of Earth Sciences monitor Indian Himalayan glaciers
ISRO uses satellite imagery (Resourcesat, Cartosat) for glacial mapping
The National Action Plan on Climate Change (NAPCC, 2008) includes the National Mission for Sustaining the Himalayan Ecosystem (NMSHE)

Connection to this news: The rapid expansion of glacial lakes documented in the Alaknanda basin (239% in 30 years) is directly attributable to the accelerated warming of the Himalayan cryosphere. The study's identification of hanging glaciers as a distinct and under-assessed hazard category adds a new dimension to GLOF risk mapping.

Disaster Management Framework for Himalayan Hazards

India's disaster management architecture under the Disaster Management Act, 2005 operates at national (NDMA — National Disaster Management Authority), state (SDMA), and district (DDMA) levels. GLOFs are classified as hydro-meteorological disasters and fall under NDMA's mandate.

National Disaster Management Authority (NDMA) under the Prime Minister has issued GLOF-specific guidelines
National Disaster Response Force (NDRF): India's primary response force for rapid deployment
Early Warning Systems for GLOFs: being developed by ISRO, IMD, and the Ministry of Earth Sciences
State Disaster Management Authority (SDMA) Uttarakhand is responsible for local preparedness and early warning dissemination
Sendai Framework for Disaster Risk Reduction (2015–2030): India is a signatory; prioritises early warning systems and risk mapping
The 2013 Kedarnath disaster (Chorabari glacial lake breach + flash floods, 6,000+ deaths) and the 2021 Chamoli disaster (ice-rock avalanche, ~300 deaths) are landmark GLOF-related events that triggered comprehensive policy reviews

Connection to this news: The study's call for basin-scale hazard assessment and monitoring of hanging glaciers is directly aligned with the Sendai Framework's emphasis on understanding disaster risk and NDMA's GLOF guidelines — and gains urgency given the post-2013 and post-2021 policy environment in Uttarakhand.

Key Facts & Data

219 hanging glaciers identified in Alaknanda basin (Central Himalaya) — study in npj Natural Hazards (2026)
Total area of identified hanging glaciers: 71.7 ± 3.5 km²; ice volume: 2.39 ± 0.42 km³
Glacial lake area in Alaknanda basin grew 239% from 1990 (0.748 km²) to 2020 (2.538 km²)
9 Potentially Dangerous Glacial Lakes (PDGLs) in Alaknanda valley; 6 in Dhauliganga valley
Himalayan region warming: 0.23–0.52°C per decade
India's Himalayan glacier count: ~9,600 glaciers covering ~16,600 km²
2013 Kedarnath disaster: Chorabari glacial lake breach → 6,000+ deaths
2021 Chamoli disaster: ice-rock avalanche (not conventional GLOF) → ~300 deaths/missing
GLOF = Glacial Lake Outburst Flood — sudden release of glacially dammed water
Alaknanda + Bhagirathi = Ganga (confluence at Devprayag)
India's glacier monitoring agencies: GSI, NCPOR, ISRO, Ministry of Earth Sciences