The devastating flash floods that swept across Nepal's Rasuwa and Dhading districts on Wednesday were triggered by a glacial collapse, not an earthquake, the US Geological Survey (USGS) has confirmed.
Initially recorded as a magnitude, 4.4 earthquake, the event was later revised to 5.2 after seismic data and satellite imagery revealed no quake had occurred. Instead, long-period seismic waves pointed to a massive glacial collapse and debris flow that unleashed catastrophic flooding downstream.
The floods originated in Tibet before surging into Nepal, leaving widespread destruction in their wake. Scientists believe a glacier perched at around 5,200 metres broke away, sending ice, snow, and water crashing into the Lhende Khola River. The impact generated tremors strong enough to mimic an earthquake.
Geomorphologist Daniel Shugar of the University of Calgary said satellite images showed the glacier had lost significant snow within 24 hours. He explained that melting snow and ice likely destabilized the glacier's base, causing it to collapse and trigger the deadly floods.
Experts warn that such glacial disasters may become more frequent as climate change accelerates melting in the Himalayas, posing grave risks to communities downstream.