Before last week’s deluge in a Himalayan valley killed more than 900 people along the border with Nepal, Chinese officials had spent months repairing the damage from an earlier landslide in the same area and trying to learn from it.
The trouble was that the next disaster was unlike anything they had prepared for.
Fourteen months earlier, a lake on a nearby glacier had burst, causing a landslide that swept away container trucks, houses, and a bridge at the Gyirong Port border crossing used by pilgrims, tourists and traders.
Afterward, the authorities closed the port for almost half a year, ordered emergency plans be updated to include the threat of glacial lake outbursts and set up a 24-hour sentry for sudden changes in water level. Construction began on a flood prevention system that included a new flood wall, reinforced dikes and channels to divert floodwaters, according to government tenders.
Gyirong County added “glacial lake outburst defense” to its training of local officials and held a special session with experts on the topic in May. Villagers near the border simulated a landslide, alerting residents through loudspeakers, WeChat messages and by knocking on doors. In July, the county’s top official inspected towns for their flood preparedness and ordered his staff to “detect early, report early and resolve early” any signs of glacial floods.
None of that preparation was enough. On Wednesday, a different hazard sent a tsunami-like wave of ice, boulders and water through the Gyirong Port complex, demolishing 27 buildings, before it surged into Nepal. Officials estimated that there were only six or seven minutes between the avalanche and when the border was hit.
On Monday, Chinese rescuers were still searching the border area and clearing roads. The landslide killed at least 903 people in Nepal and 16 in Tibet. In Nepal, 4,247 people were missing as of Monday, including 592 foreigners, the country’s disaster agency said. In Gyirong County in Tibet, 546 people remained missing, Chinese state media reported.
“It’s spooky that a different, strange, climate-related event happened in the same river just a year later,” said Austin Lord, a senior fellow at the Stimson Center who studies disaster and climate risk in the Himalayan region. “I think this event really is yet another wake-up call.”
Both disasters sent torrents of water, rock and debris hurtling downstream. But Wednesday’s came from another phenomenon that the monitoring systems were not built to anticipate — ice collapsing from a glacier, according to geologists, that could have been caused by thawing permafrost and weakened bedrock.
Chinese scientists are working on an early warning system for ice avalanches in a different part of Tibet, the southeastern Sedongpu Valley. In Gyirong, though, monitoring the area’s more than 200 glacial lakes for potential breaches has been the priority.
Why Was the Crossing Built There?
The fact that the same area was hit twice by catastrophic glacier-linked flash floods in 14 months also raises questions about why settlements and major infrastructure were built downstream in a narrow valley gorge.
For the last decade, the Gyirong Port has been the main link between China and Nepal, accounting for almost a third of China’s trade with Nepal, much of it electric vehicles going to Nepal, as well as more than 180,000 people traveling between the two countries.
The five-story complex was in one of the most vulnerable places possible for a border crossing. It perched on a narrow strip of land in a steep gorge where two rivers meet. Both rivers, fed by glaciers, descend about 10,000 feet before they come together at Gyirong Port.
“That flat ground is exactly where the bridge, customs yard, dry port and truck park sit so they take the direct hit every time,” said Saswata Sanyal, a specialist in disaster risk reduction at the International Center for Integrated Mountain Development, or ICIMOD, an intergovernmental group that has studied the border region. “People were swept away from the customs yard in 2025 and the same sites were struck again this year.”
But experts say there are few alternatives in this steep mountain region where disasters continue to strike. The Gyirong border crossing only became a major trade route over the last decade after another crossing further east, between Zhangmu in China and Kodari in Nepal, was damaged in the 2015 Nepal earthquake.
According to a travel advisory on Sunday issued by the U.S. Embassy in Beijing, some travelers have been directed to use the Zhangmu crossing. That area was also hit by a glacier lake flood in 2016 and is downstream from another large glacial lake that needs to be monitored, according to Dr. Lord of the Stimson Center.
“It’s like Whac-a-Mole. You have risks emerging in one place and you shift to another location,” he said.
A study in 2024 by Chinese researchers in Chengdu had concluded that of the transportation corridors between Nepal and China, the border crossing at Gyirong was at the highest risk of glacial lake outburst floods.
On Monday, the state-run China National Radio ran an article titled “Why is the Gyirong Port built in a deep river valley?” in an apparent effort to head off criticism of the border’s location.
“History showed it was relatively safe, especially for a border crossing like this, which is why such a route was built,” Tian Bingwei, associate professor at the Institute for Disaster Management and Reconstruction of Sichuan University, told the radio station.
Disasters More Difficult to Predict
The region has always experienced landslides, avalanches and floods but rising temperatures have made those events more destructive, complex, and difficult to predict.
The landslide last week as well as the one in 2025 exhibited what experts call a “cascade of hazards,” where several disasters happen one after another, compounding and interacting with each other.
Liu Weiming, a researcher at the Chinese Academy of Sciences’ Institute of Mountain Hazards and Environment, told China National Radio that Wednesday’s disaster was caused by new factors such as the increase in global warming that causes glaciers to melt more rapidly.
“In this case, the ice avalanche directly transformed into a debris flow without any pause, moving at an exceptionally high speed. This is extremely rare in our country,” he told the radio station.
The disaster shows that traditional monitoring that focuses on threats in isolation like a flood or an avalanche are not enough. “These mountains are very different from anywhere else. We need to understand the mountain risks and hazards much more closely going forward,” said Dr. Sanyal of ICIMOD.
“We cannot just think traditionally as we think of a single hazard,” said Dr. Sanyal. “There were sensors for flood, flash flood risk, right? But there were not sensors for this kind of ice avalanche.”
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