The devastating flash floods that struck Nepal on Wednesday was caused by a ‘glacial collapse’ and a ‘debris flow’ that ultimately led to the disaster that left overย 160 people dead, said the United States Geological Survey (USGS) on Thursday.
The USGS’s clarification comes after earlier speculations suggested that an earthquake could have triggered the flash floods.
According to the agency, the “glacial collapse and debris flow” had caused the “subsequent catastrophic impacts downstream”. It, though, noted that a 5.2 magnitude seismic event occurred around 8.37 am local time near the border of Nepal and China.
“This event was initially reported as a magnitude 4.4 earthquake,” the USGS said in a statement. “Additional analysis of nearby seismic stations, long period seismic waves, and satellite imagery led to the determination that the seismic event was instead a glacial collapse and debris flow, and that no earthquake had occurred.”
Nepal, a GLOF-prone landlocked countryย
Nepal, a landlocked nation between India and China, is prone to such glacial lake outburst flood (GLOF), which is a sudden release of large volume of waters from melting glacier-fed lakes. Nepal’s Rasuwa district was struck by a similar incident in 2025 that had claimed nine lives and left 19 people missing.
Scientists have attributed global warming to such incidents. Speaking to AFP, Dorothy Heinrich, a researcher at the UK’s University of Reading, has said that a firm link could only be made through an event attribution study, though.
“In these mountain environments, the rivers can be quite narrow in areas,” she said, adding anything that blocks them can lead to a “big accumulation of water, then it creates these incredibly fast floods.”
“We do know what climate change trends look like in the Himalayas. The high confidence of more heat waves, glacial retreat, permafrost reduction, these sorts of things that can drive things like landslides and glacial outburst floods,” said Heinrich.
Nepal scrambles for rescue operation
Following the disaster, Nepal has launched a massive search and rescue operation, with Prime Minister Balen Shah chairing a high-level meeting to assess the situation. Shah has expressed condolences to those who lost their family members and have directed officials to provide all necessary assistance to the affected.
According to government, the flash floods washed away 19 motorable bridges and around 80 security personnel, including 44 Nepal Army officials, remain missing. It has also damaged eight operational hydropower projects with a total capacity of 354 MW and five under-construction projects located in Nuwakot and Rasuwa districts.
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