China and Nepal built an early warning system for melting glaciers in Himalayas. Does it work?

Chinese scientists have developed a cross-border early warning system with counterparts in Nepal to monitor Himalayan glacial lake outburst floods. The system has issued timely alerts over the past several years, effectively preventing casualties.
But on Wednesday, a high-altitude ice-rock avalanche took everyone by surprise. The debris flow hit a river in Nepal, generating a devastating flash flood that swept all the way down to Gyirong county in China’s Tibet region. As of Thursday afternoon, nearly 300 people were confirmed dead and more than 1,000 reported missing in all.
Some experts believe the disaster was triggered by glacial rock collapse.

It remains unclear whether the China-Nepal early warning system had detected an anomaly before this disaster or issued an alert. But coincidentally, a paper published on Wednesday by the project team highlighted several of China’s recent successes.
“These include the Himalayan glacial lake monitoring network established under the second Qinghai-Tibet scientific expedition, as well as early warning systems for ice avalanche disasters in the Yarlung Tsangpo River’s Sedongpu area and for the Cirenma Co glacial lake in the cross-border China-Nepal basin,” the team wrote in the paper for the peer-reviewed Journal of Glaciology and Geocryology.
“Together, these systems have successfully issued seven early warnings [including one at the China-Nepal border last year],” they said, without specifying the latest case.
The South China Morning Post has reached out to lead author Wang Weicai and the Chinese Academy of Sciences (CAS) for comment.
“High-altitude ice-rock avalanches release enormous energy and are far more destructive than typical glacial lake outburst floods,” a glaciologist from a research institute in Chengdu, Sichuan province, told the Southern Weekly on Thursday.
Kang Shichang, a mountain hazards expert with the Chinese Academy of Sciences, pointed to the challenges of early warning systems along transnational terrain.
“In theory, detecting an ice-rock avalanche upstream could give about 20 minutes of warning. But monitoring equipment is limited at that area, and the source of the disaster is on the Nepalese side. By the time sensors pick up anything unusual, the mudslide may already be on its way,” Kang told The Paper on Thursday.

The Tibetan Plateau and its surrounding areas are home to more than 100,000 glaciers. As global temperatures rise, these are melting at an accelerating rate, bringing a host of climatic and ecological consequences.
The most visible manifestation of this trend is the growing frequency of glacial lake outburst floods.
In 1981, the Cirenma Co glacial lake on the China-Nepal border burst, destroying the China-Nepal Friendship Bridge and claiming more than 200 lives in the Himalayan country.
From 2011 to 2020, there were over 15 such floods per year on average – three times the rate from 1981 to 1990.
Chinese Qinghai-Tibet expedition findings published in 2025 identified 1,256 high-risk glacial lakes in the region – 182 of which posed an extremely high danger of outburst flooding.
A research team with CAS’ Institute of Tibetan Plateau Research began work in 2017 to build the multidimensional, cross-border disaster warning system. Using satellite remote sensing, ground-based monitors and field observations, the team established a preliminary network that has already successfully identified and issued alerts for multiple potential disasters.
Xu Baiqing, deputy director of the institute, told a conference in Nepal in May that the early warning system continuously tracked changes in glacial lake area, water levels, glacier dynamics and the surrounding weather.
On July 7 last year, patrols along the Boqu River in Tibet’s Nyalam county noticed the water had turned cloudy – a clear warning sign of a possible glacial outburst or mudslide. They reported it immediately, and local authorities quickly evacuated downstream residents.
The next day, a 0.68 sq km (680,000 square metre) glacial lake on Purepu Glacier in Gyirong county ruptured. The resulting outburst flood triggered a deadly cross-border mudslide that destroyed the China-Nepal Friendship Bridge, over a kilometre of highway and four hydropower stations. At least 18 people were killed and scores of others were reported missing.
The tragedy occurred in part because the lake that burst had not been designated as a key monitoring target by the early warning system, Xu told the Kathmandu meeting.
“It also highlighted the inherent challenges of these events, which are highly sudden and can have enormous cross-border impacts, leaving downstream areas with extremely limited time to respond once an outburst begins,” he added.

While the exact cause and full impact of the latest tragedy have yet to be officially confirmed, what is clear is that climate change is rapidly increasing the region’s vulnerability.
Temperatures in the Himalayas are rising at more than twice the global average. Warmer weather is causing surface meltwater to seep through cracks deep into the glaciers, undermining their stability, while existing glacial lakes continue to expand.
A study published last December by Zhang Guoqing and others from the Institute of Tibetan Plateau Research warned that without intervention, the intensity of glacial lake outburst floods in the Himalayas was projected to rise by more than 27 per cent.