The source of the recent ice-rock avalanche and mudslide disaster in Gyirong County, southwest China's Xizang Autonomous Region, was located on the northern slope of Nepal's Langtang Lirung peak, which posed a major challenge for monitoring and early warning, experts said at a media briefing on Sunday.

Su Pengcheng, a researcher at the Institute of Mountain Hazards and Environment under the Chinese Academy of Sciences, said the ice-rock avalanche began at an altitude of about 5,200 meters, rapidly descended, scoured the mountain slopes and developed into a massive mudflow. The flow traveled about 22 kilometers before reaching Gyirong Port in China at an elevation of around 1,800 meters. The entire process took just six to seven minutes and caused severe damage downstream.

Following the disaster, runoff in the river channels has continued, with large amounts of loose glacial moraine and debris remaining along the channels, creating a potential risk of secondary blockages and barrier lakes. Experts warned the main secondary risk is that large ice-rock collapses could block the river channel, posing a threat to rescue personnel downstream.

Therefore, authorities have conducted a comprehensive survey of geological hazards in the Donglin Zangbo river basin. Remote sensing analysis, along with field surveys, show that the basin contains 26 glaciers larger than 1 square kilometer and 11 glacial lakes larger than 0.1 square kilometers, requiring continued monitoring.

Given that Gyirong Port is located in a remote, high-altitude region along the China-Nepal border, monitoring the ice-rock avalanche source area is highly challenging. The source area is cold, oxygen-deficient and difficult to access, while cross-border river basins create observation gaps and ground-based equipment faces difficulties in power supply, communications and maintenance. The hidden nature of disaster-chain precursors leaves only a few minutes for early warning, making traditional point-based monitoring unable to cover risks across the entire basin.

Considering the conditions of Gyirong Port, Su said future work should focus on three key areas: enhancing scientific understanding of disaster chains, developing integrated monitoring technologies and strengthening cross-border cooperation.

Improving research and early identification of warning signals

The occurrence of ice-rock avalanches in the Himalayas is significantly driven by climate change, and the region is characterized by complex and diverse geological conditions and frequent tectonic activity, said Su.

As climate change increases the frequency of rare and extreme disasters, researchers should strengthen early assessment of glacier instability, close monitoring gaps at hazard source areas and introduce new geophysical detection technologies to track the entire disaster chain to obtain more reliable precursors and provide a strong theoretical basis for accurately assessing disaster risks.

These findings should also be linked with evacuation plans for downstream communities to improve the accuracy and effectiveness of warnings.

Building integrated space-air-ground monitoring system

Su proposed developing a non-contact monitoring network combining satellites, aerial platforms and ground-based technologies to reduce reliance on monitoring stations in extremely high-altitude areas that are difficult for people to access.

The expert said researchers should strengthen the development of equipment adapted to high-altitude and cold environments. He also suggested a three-level monitoring model – satellite-based wide-area screening, intensified monitoring of high-risk locations and emergency alerts for downstream areas – to provide more time for evacuation.

Strengthening cross-border cooperation

Cryosphere-related compound disasters are natural processes that are not constrained by national borders and the location of the upstream hazard source outside China is currently the biggest weakness in monitoring, Su said.

He called for leveraging international cooperation platforms to promote river-basin-level data sharing and joint risk assessments with countries in the Himalayan region, while establishing rapid channels for cross-border early warning information to extend early warning coverage across the entire basin.