Himalayas face severe glacial flood risks in years ahead, UN official warns

The Himalayas will experience serious risks of future glacial floods, according to the senior UN official, as the casualty number from the last week's flood caused by the collapse of a glacier in Nepal reached 1,000 people.

Not only the hydro-electricity relied upon by many but even entire riverbanks where millions of people live may become uninhabitable.

"Technology cannot go fast enough to save from loss these massive river systems which catch the overflow of the glacier lakes," Kanni Wignaraja, assistant secretary-general at the UN told Reuters in an interview.

There were 47 potentially dangerous glacial lakes in Nepal, China and India found by researchers in 2020. However, the number has been already much larger than that since then.

"It goes into millions the population at risk," said Wignaraja who is also the regional director for Asia and the Pacific at the United Nations Development Programme (UNDP), citing the new data prepared in June by UNDP and its partners.

Last week's devastating flood in Nepal was triggered when parts of a glacier near the Langtang Lirung mountain peak collapsed and fell to the valley floor, unleashing a landslide that sent a flood wave down the Trishuli River.

Glacier lake outbursts are a somewhat different phenomenon; they happen when melting glacier water builds up behind a natural barrier, with pressure eventually resulting in a break or overflow that sends a flash flood downstream.

Both threats are on the rise, UN officials say, as climate change accelerates glacier melt in the region, loosening rocks and putting more pressure on glacier lake barriers.

The region's mountains are also relatively young, Wignaraja said, and thus more liable to tectonic shifts that can also trigger sudden glacier or lake barrier collapses.

Researchers have found potentially dangerous glacial lakes across large parts of the Hindu Kush region.