Glacial Collapse at Nepal-China Border: Over 270 Dead, Hundreds Missing
Theo Al Jazeera English
A rare glacial collapse near the Nepal-China border unleashed a deadly flash flood, killing over 270 people and leaving more than 1,500 missing, including hundreds of foreign tourists. The disaster struck on August 26, with the worst damage in Nepal's Rasuwa district, as water levels in the Trishuli River surged by 9 meters in 30 minutes. Experts are examining whether climate change played a role, noting a clear warming trend in the Himalayas.
A rare flash flood caused by a glacial collapse near the Nepal-China border has caused severe devastation, killing more than 270 people and leaving over 1,500 missing, including more than 800 foreign tourists. Authorities fear the death toll could rise as rescue teams reach areas isolated by destroyed bridges and highways.
The flash flood occurred on August 26 (local time) in the high mountain region bordering Nepal and Tibet, with the worst damage in Nepal's Rasuwa district, just south of the Chinese border. The initial floodwaters surged into the Lhende River, then poured into the Bhote Koshi and Trishuli rivers, sweeping away homes, vehicles, and bridges in mud and debris. Water levels in the Trishuli River rose by up to 9 meters in just 30 minutes.
Initially, authorities suspected a magnitude 4.4 earthquake might have triggered the flood, but the US Geological Survey (USGS) and several experts confirmed that the "seismic event" was a consequence of "a glacial collapse and debris flow" that caused the downstream disaster, not the cause.
What is Glacial Collapse?
Glacial collapse refers to the phenomenon where a large mass of ice detaches from a glacier, potentially containing millions of cubic meters of ice, rock, and water, forming a rapid avalanche or debris flow. The term is not formally defined in glaciology but is widely used to describe similar disasters.
According to initial research from Planet Labs satellites, a landslide and ice avalanche created a debris-laden flood on the Lhende River in Tibet, about 20 kilometers northeast of the Rasuwagadhi border crossing in Nepal.
Geologist Prakash Pokharel of Nepal's National Disaster Risk Reduction and Management Authority said the disaster was caused by "an avalanche of ice and rock" on the Nepalese side. Vikram Gupta, a geology expert at Sikkim University in India, confirmed that "a significant portion of the glacier peak collapsed, carrying with it a large amount of rock and sediment." Dan Shugar, an earth scientist at the University of Calgary in Canada, said satellite imagery showed the lower part of the glacier broke off at an altitude of about 5,200 meters and plunged 1,200 meters into the valley below.
Is Climate Change the Cause?
Experts say it is too early to definitively conclude that climate change directly caused this flash flood, but they stress it is one of the growing hazards in the context of global warming.
Dorothy Heinrich, a researcher at the University of Reading in the UK, said: "We know the climate change trends in the Himalayas well. There is high confidence in heatwaves, glacier melt, and permafrost degradation—factors that can trigger landslides and glacial lake outburst floods."
Himalayan glaciers are losing ice mass 65% faster during 2011-2020 than in the previous decade. According to the United Nations, Nepal's glaciers have lost nearly a third of their volume over the past three decades due to global warming.
However, hydrologist Hatim Sharif at the University of Texas at San Antonio noted the anomaly that there was no rainfall before the flash flood, rendering traditional flood warning systems nearly useless. "By the time you see the debris flow coming, it is too late. Running or driving is futile because the fast-moving debris forms a deadly mixture like liquid concrete," he said.
How Frequent Are Glacial Collapses?
Tibet is considered the site of the largest recorded glacial collapses, although scientists still regard the phenomenon as rare.
In 2016, two successive glacial collapses in the Aru range (Tibet) released up to 83 million cubic meters of ice, killing nine herders. In 2018, two ice-rock avalanches in the Sedongpu basin (Tibet) blocked the Yarlung Tsangpo River, creating a dangerous lake. In 2022, about 40 million cubic meters of melting ice at Bukadaban Feng in the Kunlun range generated a 13-meter-high wave on a lake below.
Beyond this region, in 2018 in Uttarakhand (India), an ice-rock avalanche on Ronti Peak killed more than 200 people. In May 2025 in Blatten, Switzerland, a large mass of rock and ice crashed down, burying several houses. Experts link these events to climate change.
In Nepal, a 68-year-old survivor named Keshav Prasad Baral recounted: "It was a massive mudflow heading straight for us. When I saw it entering the house, I tried to grab my wife and head to the rooftop, but she was swept away."
