In Nepal, a river floods without rain for the second time - critical summary review

A wall of mud and water came down a Himalayan valley on Wednesday morning, tore through villages on both sides of the Nepal-China border and kept going downstream, ripping a metal bridge off its supports and collapsing multi-storey buildings into the river. It had not been raining.

That last detail is the one to hold on to. Flash floods in South Asia are usually a monsoon story: June to September, days of rain, saturated slopes, rivers over their banks. This was not that. "There was no rain in Nepal, so we did not expect anything like this," said Narendra Pariyar, the district administrator of Rasuwa, one of the worst-hit areas, according to the French news agency AFP. What hit the Bhote Koshi river system came from higher up — from ice and rock, not from the sky — and it is the second time in 14 months that the same watercourse has done this.

What is known about the scale

The counts moved through the day and will keep moving. Nepali police confirmed eight bodies recovered in the morning; local police in Bagmati province later put the figure at 17, and other outlets reported 18 and 19 as the day went on. Officials in both countries said they expected the toll to rise.

The number that gives the real scale is the missing. Nepal's tourism board said 384 travellers could not be accounted for in the affected areas — 291 foreign nationals and 93 Nepalis, including guides. The nationalities listed span India, the United States, the United Kingdom, Malaysia, Australia, the Netherlands and South Africa. Nepal's foreign minister, Shishir Khanal, told parliament that 26 police officers, nine armed police and 44 military personnel were also missing. Sixty workers at an under-construction hydropower project were unaccounted for, according to Nepal's state news agency RSS.

Rescue was slow for a physical reason: the water was too high for helicopters to land in Syapru Besi and Timure, army spokesman Raja Ram Basnet said, even after more than a dozen aircraft were sent. "There is devastation everywhere we look," Tula Bahadur BK, a health worker in Rasuwa, told the Reuters news agency. "The settlements next to the river have been completely swept away. Five of my own relatives are missing."

On the Chinese side, in Tibet's Gyirong county, state broadcaster CCTV reported "major casualties and missing people" at Gyirong port, the main land crossing between the two countries, with roads, communications and power cut. Xi Jinping ordered an "all-out" search effort and called for stronger monitoring and early warning systems to prevent secondary disasters. Vice Premier Zhang Guoqing was sent to Tibet, and an initial team of 200 geological and emergency personnel was mobilised with drones and life detectors, CCTV said.

Earthquake or glacier: the cause is still contested

Two explanations were circulating within hours of the flood, and they were not the same explanation.

The Nepali government's version is seismic. "An earthquake occurred at 8:37 a.m. today, and due to it, a large landslide occurred, blocking the river, which appears to have caused the flood," Khanal told the House of Representatives. The United States Geological Survey did register a 4.4-magnitude earthquake in the region at that time.

The scientific version is glacial. Researchers at the International Centre for Integrated Mountain Development (ICIMOD), a Kathmandu-based climate research group, say what came down was ice and rock. "The Lhende Khola has flooded twice in fourteen months, this time triggered by an ice rock avalanche from a glacier on the Nepal side that blocked the river and released a sudden surge downstream," said Saswata Sanyal, a disaster risk reduction specialist there. Sarthak Shrestha, a remote sensing analyst at the same institution, told AFP that a preliminary assessment showed "no anomalies" on the Chinese side: "We believe a rock-ice avalanche occurred in Nepal, blocking the Lhende river and causing the cascading flood event."

Both versions share a mechanism, and that mechanism is what matters. Something blocked a narrow mountain river, water piled up behind the blockage, and the blockage gave way at once. Qianggong Zhang, ICIMOD's head of climate and environmental risks, told AFP the exact cause was still to be determined.

The same river, 14 months ago

This is where the event stops being a one-off. Last year, a flash flood on the Bhote Koshi killed nine people, left 24 missing and washed away the "friendship bridge" linking Nepal and China, disrupting trade and transport for months. That flood was traced to the draining of a supraglacial lake in Tibet — meltwater pooled on top of a glacier that let go when temperatures rose.

The infrastructure damage repeated too. Gyirong port lost its bridge to Nepal's Rasuwa port in July 2025, and goods trade was suspended for roughly six months, Chinese state media reported at the time. In July of last year, 17 people went missing in a mudslide near the same port, according to the Chinese state news agency Xinhua.

The reason this keeps happening has a measurement behind it. Researchers in Kathmandu found earlier this year that glaciers across the Hindu Kush Himalaya are melting at an accelerating rate, with ice loss rates doubling since 2000, driven by rising global temperatures. Sanyal's comment on Wednesday was blunt about the gap that leaves: "In a warming Himalaya, early warning is the first line of adaptation."

The risk has not passed

The most consequential sentence of the day was not about the dead. Zhang, of ICIMOD, told AFP that a second flood may be coming: "With a blockage still lodged upstream on the Nepal-China border river, authorities warn a second flood may occur."

In other words, whatever dammed the river has not fully cleared. Nepali authorities alerted residents along the Bhote Koshi, Trishuli and Narayani rivers to stay away from the banks, and Prime Minister Balendra Shah said instructions had been given to move people in lower areas to safer ground. Traffic authorities in Tibet's Shigatse said roads in the area were "at risk of mudslides and unsafe for passage".

What the water took besides villages

Rasuwa is roughly 50,000 people, a border road, a national park and a string of hydropower plants built to use exactly the fast-flowing rivers that flooded. The Nepal Electricity Authority said about 430 megawatts of generating capacity, mostly hydro, was damaged — more than 12% of the country's 3.2 gigawatts of hydropower capacity, by a Reuters calculation. Nepal's Independent Power Producers' Association said 14 projects were affected, five of them still under construction.

Trade took the other half. Gyirong port handles hundreds of millions of dollars in annual two-way commerce and accounted for nearly a third of China-Nepal trade volume in 2024, according to Xinhua. Roads to it were closed to non-emergency vehicles for seven days.

And then the pilgrims. Nepal's tourism board said most of the missing travellers were likely Indians and members of the Indian diaspora on pilgrimage to Mount Kailash in Tibet, a sacred site for Hindus. Malaysia's foreign ministry said travel agencies had lost contact with 11 Malaysians believed to be in Rasuwa. South Korean officials said citizens working on a hydropower plant in Nepal were among the missing.

What is known — and what is still unknown

What is established: a sudden surge came down the Lhende Khola into the Bhote Koshi on Wednesday morning without rainfall; villages, a border crossing, bridges and hydropower plants on both sides were destroyed; hundreds of people, most of them travellers, are unaccounted for; and the same river did something similar 14 months ago, from a different but related glacial trigger.

What is not settled: whether the trigger was an earthquake-driven landslide, as Nepal's foreign minister told parliament, or an ice-rock avalanche, as ICIMOD's researchers describe it; how many died on the Tibetan side, where Chinese authorities have reported "major casualties" without figures; and when — or whether — the blockage still sitting upstream will release.

If you have a trek, a Kailash pilgrimage or any travel through these valleys booked in the coming weeks, that last point is the operational one: the warning about a second flood came from ICIMOD and from authorities in both countries, and it applies to river valleys downstream, not only to the immediate disaster zone. Check ICIMOD and local advisories before approaching the Bhote Koshi or Trishuli corridors, and note that the main road from the border to Kathmandu was closed.

For everyone else, the thing worth following is not the death toll, which will change with every bulletin. It is whether Nepal and China install early warning systems on this stretch. Xi called for stronger monitoring; Sanyal called early warning the first line of adaptation. The river has now given the same warning twice.