A massive glacier collapse may have triggered the catastrophic flash flooding that struck Nepal near its border with Tibet, leaving nearly 170 people dead and about 1,500 missing, experts said.
The disaster struck Wednesday in Nepal’s mountainous Rasuwa district, where a torrent of water, rock, ice and sediment swept through river valleys. At least 700 foreigners are among those reported missing, and authorities fear the death toll could rise significantly as rescue crews search the devastated region.
Satellite images from Planet Labs indicate that the lower portion of a glacier broke away at an elevation of about 5,200 meters, or 17,000 feet, before plunging roughly 1,200 meters to the valley floor. Scientists believe the collapse gathered additional rock and sediment as it descended, producing an enormous debris flow.
Before-and-after satellite images show previously green mountainsides buried beneath brown sediment and debris.
Nepali officials initially suggested an earthquake might have contributed to the disaster. However, the U.S. Geological Survey said seismic activity detected in the area was apparently caused by the collapse of rock and ice itself rather than an earthquake that preceded it.
Scientists also noticed evidence of unusually rapid snowmelt before the collapse. Satellite images showed several glaciers that had been covered with snow becoming largely bare within about 24 hours, suggesting unusually warm conditions.
Whether climate change contributed directly to the disaster remains under investigation. Nepal’s glaciers have lost nearly one-third of their ice in just over three decades, according to the United Nations, which reported in 2023 that the country’s glaciers had been melting 65% faster during the previous decade than in the decade before that.
Nepal’s National Disaster Risk Reduction and Management Authority said an ice-rock avalanche about 12 miles northeast of a Nepal-China border crossing triggered flooding in the Lhende River.
The resulting surge raced through the Bhote Koshi and Trishuli river systems, carrying water, boulders and sediment downstream. In one area, river levels reportedly rose as much as 30 feet in just 30 minutes.
Several hydropower projects are located in the hardest-hit region, adding to concerns about the disaster’s long-term effects.
Source: Reuters