Nepal floods of 2026

Nepal floods of 2026, catastrophic flash flood and debris flow triggered by the partial collapse of the glacier sitting atop Langtang Lirung peak in Langtang National Park, Nepal, that devastated a river valley shared by Nepal and China on August 26, 2026. At least one smaller flood resulted from the breach of a temporary barrier lake (a lake formed by debris that cut across an existing stream) that was created by the initial surge. In the months following the flood, Nepali and Chinese officials reported that nearly 1,500 people had been killed and more than 5,000 remained missing. Nepali authorities placed the cost of the disaster and recovery efforts at roughly $4.8 billion (see also natural disaster).

Cause

The glacier’s partial disintegration appeared to have been caused by the breakdown of supporting bedrock underneath the ice; however, some authorities suggest that part of the glacier may have been destabilized by a period of warmer-than-average temperatures driven by a warming climate (see global warming). The sudden failure of the bedrock produced an avalanche of rock and ice that tumbled some 3,900 feet (about 1,200 meters) down a steep mountain slope into the Lende Khola. (The Lende Khola is a tributary of the Trishuli River, both of which are part of the Bhote Koshi river system that flows south out of the Himalayas.) As the avalanche progressed, heat generated by the grinding friction of the ice against the mountain slope and the against the rock entrained in the landslide is thought to have converted much of the ice to liquid water.

Some accounts noted that the avalanche created a temporary dam across the Lende Khola, but it lasted only minutes before water collecting behind it caused it to breach. Others, however, suggested that this cascade of 55 million tons (about 50 million metric tons) of ice and rock developed into a fast moving surge of water, sediment, melting ice, and debris. The surge swelled the river by at least 230 feet (70 meters) above normal levels within the narrow high-mountain gorges and by roughly 30 feet (9 meters) in 30 minutes downstream. According to some accounts, the flow’s velocity approached 93 miles (150 km) per hour in some locations.

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Piled debris that created a number of barrier lakes in the valley contributed to ongoing flooding hazards as water continued to build up behind the dams. A small breach in a dam holding back water from one of the barrier lakes halted rescue operations for a time on August 28.

Damage

Traveling some 60 miles (100 km) downstream along the Trishuli River, the surge washed over and buried whole villages, blocked hydroelectric power tunnels, destroyed bridges and roads, and swept away thousands of structures. Roughly 7,500 homes were completely destroyed, and some 20,000 more were damaged. One of the first locations struck by the surge was the Gyirong border port, where the installation’s 65-foot- (19.8-meter-) tall main building was overwhelmed by the height of the fast-moving water and washed away. Further downstream, several settlements, including the villages of Syapru Besi and Timure, were inundated by mud and debris, and the surge also pulled down numerous bridges across the river valley.

Relief and recovery

In the days following the disaster, hundreds of people were rescued from the remains of buildings isolated by the flood and from mud-filled hydroelectric tunnels, largely by Nepali and Chinese rescue teams. Nepal and China were very selective about outside help, largely limiting search, rescue, and recovery operations and technical assistance to their own teams and to disaster specialists from India, Australia, and South Korea. The United Nations Fund for responding to Loss and Damage and the World Bank reported that more than $820 million had been pledged by the international community and nongovernmental organizations to support recovery efforts.