Glacier Collapse Triggers Deadly Nepal-Tibet Flash Flood

Nepali officials initially attributed the disaster to a magnitude 4.4 earthquake, but the United States Geological Survey (USGS) later concluded that no earthquake had occurred. What seismic stations detected was a huge mass of rock and ice breaking off a glacier and thundering onto a valley floor, registering as a magnitude 5.2 landslide. Dr Simon Cook, a glacier specialist at the University of Dundee, traced the failure to a glacier near the Langtang Lirung peak, about 15 kilometres west of the flood site. Nepal's national disaster authority said satellite imagery showed the ice and rock crashing into the Lhende River, where the debris churned into a fast-moving slurry of mud and rubble that surged down the valley. Scientists describe compounding causes: tectonic forces are still pushing the Himalayas upwards, steepening the glaciers clinging to them, while rising temperatures thaw the ice and permafrost that hold mountainsides together. Researchers called the collapse of an entire glacier "in one go" highly unusual.

Downstream, the Trishuli River rose by roughly eight metres in half an hour, and survivors described a wall of water arriving with almost no warning. Bodies were recovered hundreds of kilometres downstream. The Nepali army airlifted more than 100 survivors, and the Red Cross estimated 1,200 residents of at least three villages were displaced. The missing included Indians, Americans, Britons, Australians and Canadians, many travelling to Kailash Mansarovar, a pilgrimage site revered by Hindus and Buddhists. United Nations Secretary-General Antonio Guterres said relief teams were being mobilised, Washington pledged $500,000 in emergency aid, and Chinese Premier Li Qiang visited the border region. The International Centre for Integrated Mountain Development (ICIMOD) reports that Hindu Kush Himalayan glaciers have been losing ice at double the previous rate since 2000.