Glacier Collapse Caused Nepal Flash Floods: US Monitor

Kathmandu: The tremors that triggered the deadly flash floods in Nepal on Wednesday morning were caused by a landslide, not an earthquake, the United States Geological Survey (USGS) clarified late Wednesday evening.

The agency said seismic activity initially reported as an earthquake “was instead a glacial collapse and debris flow” that “caused subsequent catastrophic impacts downstream.”

At 8:37 am Nepal time, the USGS said Thursday reported seismic activity as a 4.4-magnitude earthquake along the Nepal-China border, north of Kathmandu. However, the agency later clarified that the event that was initially reported as an earthquake “was instead a glacial collapse and debris flow.”

“No earthquake had occurred.”

An initial study of Planet Labs satellite imagery indicated instead that a landslide of ice and rock triggered a debris-laden flood in the Lhende River, about 20 km (12 miles) northeast of the Nepal-China Rasuwagadhi border crossing.

Lhende Khola River is a tributary of the Bhote Koshi that flows from China into Nepal. The flash floods that followed and killed over 157 people were thus caused by this exceptionally powerful landslide, later registered as equivalent to an earthquake measuring 5.2