Nepal flood death toll passes 600 as new landslide-dammed lake threatens a second surge

Rescue teams in the Nepali Himalayas entered a fourth day of search operations on Saturday, working through mud, washed-out roads and intermittent helicopter groundings to reach survivors of a flash flood that has killed more than 600 people and left thousands still missing along the Nepal-China border.

The flood tore down the Bhote Koshi and Trishuli river valleys on the morning of August 26, after a mass of rock and glacial ice broke away high in the mountains near the frontier with Tibet. It scoured a roughly 70-kilometer stretch of riverbank settlements in Nepal's Rasuwa, Nuwakot and Dhading districts, destroyed the Gyirong Port trade complex on the Chinese side of the border, and swept through hydropower construction sites where more than a thousand workers were on shift when the water hit.

The toll, still rising

Nepal's disaster authorities said Saturday that confirmed deaths in the country had passed 600, according to figures reported by CBS News. Roughly 1,924 people remain unaccounted for in Nepal and an additional 558 in the Tibet Autonomous Region, putting the combined confirmed missing figure at just under 2,500. Officials describe even that tally as provisional: large sections of the disaster zone remain reachable only on foot or by helicopter, and poor weather grounded aerial searches for a second straight day. Some Nepali outlets have circulated far higher, unconfirmed estimates of people unaccounted for, but authorities have not verified those figures and continue to work from the lower, cross-checked count. More than 3,700 survivors have been pulled from the wreckage so far.

The U.S. State Department said it was still trying to pin down how many Americans were affected, after the number of citizens reported missing fluctuated through the week. The Isha Foundation, an India-based organization that had run a pilgrimage to Mount Kailash on the Tibetan side of the border, said 22 of the roughly 80 missing members of its group were American citizens — 13 women and nine men — among pilgrims drawn from 19 countries.

A glacier gives way, in a pattern scientists have seen before

Researchers at the International Centre for Integrated Mountain Development, the Kathmandu-based regional body that monitors Himalayan hazards, said the likeliest trigger was an ice-and-rock avalanche near an elevation of roughly 5,200 meters, which fell about 1,200 meters into a side valley called the Lhende Khola. Writing for the UK's Science Media Centre, Professor Maria Shahgedanova of the University of Reading said the failure involved "a large rock and ice avalanche at around 5,200m above sea level, when a huge section of glacier and the underlying bedrock, estimated to be between 1 and 1.3km wide, detached" from the Langtang Lirung massif. Dr. Richard Waller, a glaciologist at Keele University, put it more simply: "a steep flank of the mountain collapsed, taking a large part of the overlying glacier with it." The debris is believed to have dammed the Lhende Khola, and when that temporary dam gave way it sent a wall of water and sediment down the Bhote Koshi into the Trishuli River, registering as a magnitude-5.2 seismic signal that briefly fueled speculation about an earthquake before geologists traced the tremor to the landslide. Gauges downstream captured the surge's speed: the Trishuli rose roughly 9 meters in half an hour at one station and about 7 meters at another.

Glaciologists say the collapse fits an unsettling pattern rather than a one-off event. Professor Bethan Davies of Newcastle University noted that "glacier collapse events have occurred regularly in recent years," pointing to the 2025 collapse of the Birch Glacier in Switzerland and the 2021 disaster at Chamoli in the Indian Himalaya, which killed more than 200 people after a rock-ice avalanche destroyed hydropower infrastructure in a similar chain of events. Dr. Hamish Pritchard of the British Antarctic Survey went further, noting that "a similar, smaller flood hit the same river last July, and the 2015 Nepal earthquake released a major avalanche down the south face of the same mountain" — meaning this slope has now produced three major mass-movement events in just over a decade. Nepali officials have described the current disaster as one of the country's worst since the 2015 earthquake, according to relief-coordination reporting from the Philippine Daily Inquirer's global desk.

"The increasing frequency of cryosphere hazards is becoming more visible than ever," said Mohd. Farooq Azam, a senior cryosphere specialist at the International Centre for Integrated Mountain Development.

Hydropower workers, trekkers and pilgrims still unaccounted for

Rasuwa district sits astride one of Nepal's busiest hydropower-construction corridors, where crews have spent the past decade building dams, tunnels and powerhouses along the same river gorges the flood swept through. Nepal's Independent Power Producers' Association has said 934 people linked to 11 different hydropower projects remain unaccounted for, and the energy ministry has put the number of sector employees out of contact above 1,000, according to the Kathmandu Post. At the 111-megawatt Rasuwagadhi Hydropower Company — a state-linked project only recently returned to full operation after an earlier flood damaged it last year — 49 employees were out of contact, with officials fearing several are trapped inside a submerged underground powerhouse. "We are hoping they are safe as long as the oxygen pipes have not been blocked," said Narayan Nath Neupane, the company's information officer. At the smaller Chilime Hydropower Project, eight workers were unaccounted for and six were believed trapped in a flooded tunnel; its executive director, Baburaj Maharjan, said the firm was "working to mobilize a rock-climbing rescue team." The Nepal Army has rescued 254 workers from the Upper Trishuli-1 project, while at Langtang Khola Hydropower, 18 were pulled out but 42 remained unaccounted for, with the site's promoter noting that with bridges swept away "there is no way to get there by road." At Upper Trishuli-3, where 213 people were initially reported missing and 85 have since been rescued, the project's executive director said the site itself had effectively become a riverbed.

The same border corridor is also one of Nepal's principal routes for pilgrims and trekkers heading into Tibet, and several tour operators have reported clients and staff among the missing. The Kathmandu-based Trekkers' Society, which organized the Isha Foundation's Kailash pilgrimage, said 77 foreign pilgrims and 12 Nepali staff lost contact around 8 a.m. on August 26, shortly after the group had cleared immigration at the Gyirong Port crossing on its way back from Tibet, according to The National. Leaf Holidays, Treks and Expeditions separately reported 55 people missing — 46 clients and nine staff, including Malaysian, Singaporean, Ukrainian, Italian, American and British nationals — also traveling from Kailash, while Kathmandu Holiday Tours and Travels listed 17 missing and Alpine Treks reported 16 foreign nationals unaccounted for, 12 of them British and four South African. Nepali tourism officials said more than 650 foreign nationals were unaccounted for in total in the days immediately after the flood, though that number has been narrowing as people are confirmed safe.

Warnings, a new hazard upstream, and what happens next

The disaster has revived a long-running debate over the limits of early-warning systems in a mountain range where thousands of glacial lakes and unstable slopes now sit above expanding settlements and hydropower sites. A senior Nepali disaster-management official said the country does have a warning system covering the region, but that "the flood developed so rapidly that people simply did not have enough time to get to safety, even though the system was functioning." Professor Hannah Cloke of the University of Reading told the Science Media Centre that part of the problem was psychological as much as technical: "This was a flood that arrived beneath clear skies... many people struggle to believe the severity of a risk because there was no local rainfall." Professor Reza Ahmadian of Cardiff University added that the underlying science remains genuinely difficult, since "it is not currently possible to predict the exact time at which a natural barrier might fail." A Kathmandu Post editorial published the day of the flood argued that Nepal and China need faster, more systematic sharing of upstream hydrological data, since hazards originating in Tibet often reach Nepali villages before any alert does.

Compounding the challenge, engineers on both sides of the border have identified a new lake, estimated at roughly 2 million cubic meters, that formed behind landslide debris near where the original slope failed. Chinese authorities warned this week that continued inflow could push the lake toward failure within days, and Nepali disaster officials issued a fresh alert on Friday after water and mud levels began rising again at the same site, a risk flagged in a rapid situation overview circulated among humanitarian agencies. Some search crews have been temporarily pulled back from riverbank areas as a precaution.

• More than 600 confirmed dead in Nepal, with additional deaths reported in Tibet
• Nearly 2,500 people remain officially unaccounted for — about 1,924 in Nepal and 558 in Tibet
• Roughly 90 Americans were reported unaccounted for at various points, including 22 members of an Isha Foundation pilgrimage group
• A newly formed debris-dammed lake upstream is being monitored for a possible second flood

International aid has moved quickly. India has put Indian Air Force C-17 and C-130 aircraft carrying earthmoving equipment, relief supplies and medicine on standby, after Prime Minister Narendra Modi told his Nepali counterpart by phone that "the people of India stand with their Nepali brothers and sisters in this difficult situation." China has pledged emergency cash assistance, with its ambassador in Kathmandu asking Nepal's finance ministry to begin the paperwork to receive the funds. The World Bank's country director for Nepal has told the finance ministry that up to 25 billion Nepali rupees could be mobilized from various sources as emergency assistance, though it remains unclear whether that would be a grant, a loan or a mix of financing — and Washington has pledged $500,000 through Catholic Relief Services for shelter and sanitation support, plus a disaster-response advisor to help coordinate the search for missing Americans.

Nepal's government has deployed thousands of army and police personnel to the disaster zone and is coordinating relief, shelter and medical support with international aid groups as roads and bridges are rebuilt, according to an appeal from the Ministry of Home Affairs. A full damage assessment will likely take weeks given how much terrain remains cut off, but the immediate priority remains the tunnels in Rasuwa and the swollen rivers below them, with the newly formed lake upstream adding urgency to a search already racing against difficult terrain — and with scientists warning that this is unlikely to be the last such event along Himalayan rivers that now carry far more people and infrastructure than they did a generation ago.