The death toll from devastating flash floods along Nepal’s border with Tibet has risen to 469, Nepal Police said on Friday, as rescue teams continue searching for people reported missing after torrents of water, mud and debris swept through the region earlier this week.
Massive landslides and flooding struck the mountainous border region on Wednesday, causing widespread destruction across northern Nepal and parts of Tibet. Rescue and evacuation efforts remain underway, with military personnel and helicopters deployed to reach isolated communities, evacuate residents and search for survivors.
The disaster has also heightened concerns about additional flooding after China issued a Level-IV emergency alert over a newly formed barrier lake near the confluence of the Chhochen Khola and Purepu Tsangpo rivers. Both rivers originate in Tibet and form part of the Bhote Koshi river system after flowing into Nepal.
China’s Ministry of Water Resources said the lake had accumulated about two million cubic metres of water by Thursday morning. With rainfall expected to continue, forecasts indicated that inflows could reach roughly three million cubic metres over the next three days, increasing the possibility that the natural barrier could fail and release a large volume of water downstream.
Authorities are keeping a close watch on the lake, rainfall and downstream river systems while assessing which communities could face the greatest danger. Areas around Gyirong Port, a key crossing on the China-Nepal border, are among those being monitored.
China has also deployed satellites, drones and unmanned aerial vehicles to assist rescue and damage-assessment operations. Satellite images are being used to evaluate the scale of destruction, while high-definition and thermal imaging equipment is helping rescue teams identify priority search areas and locate possible survivors in vegetation and mud-covered terrain.
Initial reports suggested that an earthquake may have triggered the disaster. However, the US Geological Survey said the event was caused by a “glacial collapse.” According to USGS data, the collapse was powerful enough to register as a magnitude 5.2 event when the glacier struck the valley floor.
Scientists believe the collapse sent enormous quantities of ice, rock and sediment into the river system, triggering catastrophic flooding downstream. Mike Searle, a professor of Earth sciences at Oxford University, said the sequence may have involved a landslide temporarily blocking the river, followed by a sudden release of the accumulated water in a powerful flood.
A massive wall of mud and water subsequently swept through northern Nepal, destroying buildings, roads and vehicles. Severe flooding was reported along the Bhote Koshi, Trishuli and Narayani rivers, while fatalities were also recorded on the Tibetan side of the border.
Scientists and disaster-response agencies are continuing to analyse satellite imagery, rainfall records and evidence of possible river blockages to determine precisely how the disaster unfolded and assess the risk of further flooding.
