How catastrophic flash flood unfolded at remote Nepal-China border point

A dark wall appears behind the buildings in Gyirong, marking the onset of a catastrophic flash flood on the Chinese side of the Nepal-Tibet border. The flood, captured on CCTV at 10:59:53, sent a wall of water, mud, boulders, ice, and rock down the valley, causing widespread destruction. Much of the border complex was swept away, with buildings vanishing from the valley floor. Electronic immigration records and insights from a surviving staff member provide some insights into the events that unfolded.

The border crossing at Rasuwagadhi, a historic travel route between Kathmandu and Tibet, was unusually busy on the morning of the flood. Over 100 Indians may have been present, including travellers, customs officials, and residents living along the border. At least 275 Indians are missing, according to India's foreign ministry. The flood struck less than 10 minutes after the final immigration transaction recorded at 08:35:03 local time.

Seismic instruments detected movement in the mountains above the border at 08:37, attributing the signal to a glacier collapse that triggered the flood. China claimed the mudslide reached the border crossing within seven minutes. The impact area included houses, hotels, local businesses, and four hydropower offices. The immigration office was situated about 100 meters above the river but was likely inundated by rising water levels.

The exact whereabouts of the missing individuals remain unclear, with estimates suggesting a flood toll of 2,000 to 2,500 people.