The deadly flash floods that swept through parts of Nepal on Wednesday were triggered by a glacial collapse and debris flow, not an earthquake, the United States Geological Survey (USGS) has clarified.
The seismic activity was initially reported as a 4.4-magnitude earthquake along the Nepal-China border, north of Kathmandu. However, the USGS later said the event had been misidentified.
The agency said the seismic activity initially reported as an earthquake "was instead a glacial collapse and debris flow" that "caused subsequent catastrophic impacts downstream."
The USGS also stated, "No earthquake had occurred."
Landslide sent debris into Lhende River
An initial study of Planet Labs satellite imagery found that a mass of ice and rock had collapsed, sending debris into the Lhende River, around 20 km northeast of the Rasuwagadhi border crossing.
The Lhende Khola is a tributary of the Bhote Koshi River, which flows from China into Nepal. The powerful collapse triggered a debris-filled flood that then swept through downstream areas.
The event was later recorded as being equivalent to an earthquake measuring 5.2, despite no earthquake actually occurring.
Rescue operations underway
Relief and rescue efforts continued in Rasuwa and other affected districts. Nepal Police had recovered 157 bodies, while authorities were also working to move families living in flood-prone areas to safer locations.
At least 403 tourists, including 341 foreign nationals, were unaccounted for several hours after the disaster, according to Nepal's tourism ministry. The missing foreigners included 142 Indians, along with nationals from Australia, Britain, Malaysia, the Netherlands, Portugal, South Africa, South Korea and the United States.
Prime Minister Balendra Shah has directed government resources towards relief and rescue operations as teams search for survivors and bodies buried under mud and debris.
Nepal and Tibet both hit
The flood entered the Bhote Koshi River around 9 am local time after crossing from the Tibet side. Rasuwa and Dhading, which border Tibet, along with Nuwakot, were among the affected districts.
On the Tibetan side, China's state broadcaster reported three deaths and 265 people missing in Gyirong. Rescue operations were underway, while authorities continued to verify the reported deaths.
Footage from the border area showed torrents of rock, mud and water sweeping away buildings and vehicles. In Nepal, damaged hydropower infrastructure left several areas without electricity as families gathered near an army training centre seeking information about missing relatives. Helicopters continued flying over affected areas, bringing survivors to safety.