The Himalayan region could face increasingly severe glacial flood disasters in the coming years as rising temperatures accelerate glacier melt, a senior United Nations official has warned.
Kanni Wignaraja, an assistant secretary-general at the United Nations and regional director for Asia and the Pacific at the United Nations Development Programme (UNDP), said millions of people living along major Himalayan river systems could be exposed to future disasters.
Her warning comes after last week’s devastating flooding in Nepal, where the reported death toll surpassed 1,000 following a disaster triggered by the collapse of a glacier near the Langtang Lirung mountain area.
Wignaraja said the scale of the region’s river systems means existing technology and infrastructure may not be sufficient to prevent widespread losses from future glacial disasters.
Millions Could Face Growing Flood Risk
Researchers identified 47 potentially dangerous glacial lakes across Nepal, China and India in 2020.
However, the number of potentially hazardous lakes is now believed to be significantly higher, according to updated information compiled by UNDP and partner organisations in June.
Wignaraja said the population potentially exposed to these risks is now in the millions.
The threat extends beyond communities living near rivers. Hydropower facilities, electricity networks, roads and other critical infrastructure are also vulnerable to sudden floods originating in the mountains.
For communities located along riverbanks, relocating to higher ground could also be financially difficult or impossible.
Glacier Collapse and Glacial Lake Floods Pose Different Threats
The recent disaster in Nepal was caused by the collapse of parts of a glacier near Langtang Lirung mountain.
The collapsing ice and material fell into the valley and triggered a landslide. The resulting flood wave then travelled down the Trishuli River.
Glacial lake outburst floods are a different but related threat.
These events occur when water from melting glaciers accumulates behind natural barriers. As water pressure increases, the barrier can eventually collapse or overflow, releasing a sudden and powerful flood downstream.
UN officials warn that both types of hazards are becoming more serious as climate change accelerates glacier melting.
Increasing temperatures can also loosen rocks and destabilise mountain slopes. At the same time, greater volumes of meltwater can place additional pressure on natural barriers holding glacial lakes in place.
The Himalayan region is also geologically active. Wignaraja noted that the relatively young mountain formations are more vulnerable to tectonic movements, which can contribute to sudden collapses of glaciers or natural lake barriers.
Nepal Faces Major Hydropower Risks
Nepal is particularly vulnerable because its economy and water supply are heavily dependent on the Himalayan glacier system.
Wignaraja said the country faces difficult choices as communities, infrastructure and economic activity remain concentrated around vulnerable river systems.
Hydropower is a major concern. UNDP said last week’s flooding affected 15 major power stations that were under construction, in addition to damage or disruption involving facilities already operating.
New technologies could help strengthen hydropower stations and electricity networks against conventional flooding.
However, Wignaraja warned that the scale of the latest disaster showed the limits of existing protective infrastructure.
She described the event as a powerful wave of mud and ice and said conventional construction could not have stopped such a force.
The growing risks highlight the need for stronger early-warning systems, resilient infrastructure and better planning for communities living in vulnerable Himalayan valleys as glacier-related hazards intensify.
