UN officials warn of the risk of floods due to glaciers increasing dangerous glacial lakes in the Himalayas

Senior United Nations officials warn that the Himalayan region is facing serious risk from future glacial floods.

The flash flood caused by avalanches in Nepal that killed more than 1,000 people last week has sounded the alarm about disasters from glaciers in the Himalayan region.

In 2020, researchers identified 47 glacial lakes at risk of unsafety in Nepal, China and India. The actual number is now estimated to be much higher. This not only threatens hydroelectric power sources in the area, but also threatens the lives of people living in riverside areas.

"Technology cannot develop fast enough to prevent damage along major river systems, which suffer from overflows from glacial lakes," Reuters on September 1 quoted Kanni Wignaraja, assistant secretary general of the United Nations.

Wignaraja, who is also the Asia-Pacific regional director of the United Nations Development Program (UNDP), said the number of people in the danger zone "numbers in the millions".

The devastating flood in Nepal last week occurred after part of a glacier near the top of Mount Langtang Lirung collapsed, falling into the valley, causing landslides and sending flood waves down the Trishuli River.

Glacial lake breach flooding is a somewhat different phenomenon, occurring when glacial meltwater accumulates behind a natural dam. The increased pressure could eventually cause dams to burst or water to overflow, sending massive floods downstream.

UN officials say both threats are increasing, as climate change causes glaciers in the region to melt faster, loosening rock structures and increasing pressure on glacial lake dams.

According to Wignaraja, the mountain ranges in this area are also relatively young, so are affected by tectonic shifts. This could trigger glacier collapses or glacial lake bursts.

Researchers have discovered many potentially dangerous glacial lakes in large areas of the Hindu Kush range. However, Wignaraja said no country in the region is more dependent on glaciers than Nepal, both for water and income.

"That leaves the country now facing extremely difficult choices," Wignaraja said.

For many people living along rivers, moving to higher ground may be beyond their financial means.

Critical infrastructure will also face many risks. Damage to Nepal's electricity production may be more serious than some previous assessments.

Mohan Kumar Dangi, president of the Nepal Independent Power Producers Association, said flash floods damaged at least 12 hydropower projects in Rasuwa and Nuwakot districts, with a total capacity of 670 MW. Of these, 4 projects are under construction, 7 projects are in operation and 1 project is in the testing phase.

Ms. Wignaraja believes that power grids and hydroelectric plants can be made more resilient to floods by applying new technology. However, last week's disaster exceeded the capabilities of existing defense measures.

"No structure can withstand this disaster," she concluded.