A high-altitude ice avalanche in Nepal triggered a chain of events that evolved into a devastating mudslide and struck Gyirong Port in southwest China's Xizang Autonomous Region, according to China's Ministry of Natural Resources.

A powerful mudslide struck Gyirong County in Xizang on Wednesday. The Ministry of Natural Resources activated a Level-II geological disaster emergency response at 3 p.m. the same day and dispatched a working group to the site to assist with emergency rescue efforts and the prevention of further geological disasters.

The high-altitude ice avalanche upstream in Nepal led to a debris flow that later developed into a mudslide, according to the ministry.

Guo Zhaocheng, a senior engineer at the China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, said high-resolution remote sensing images and expert analysis show that the high-altitude ice avalanche occurred on the upper reaches of Cuojian, a tributary of the Donglin Zangbo River in Nepal.

The collapsing ice scraped up moraine deposits along the valley, forming a high-speed debris flow that continued downstream before evolving into a mudslide, which surged toward Gyirong Port, causing major casualties.

Experts believe the ice avalanche originated in a glacial area at an elevation of 5,200 to 5,500 meters. Falling from such a high altitude, the massive collapse released enormous potential energy, forming a high-speed debris flow that eventually evolved into a mudslide.

Glaciers are constantly moving, carrying rocks from high mountain areas downstream. But in areas with particularly steep terrain or heavily fractured geological structures, the glacier and surrounding rock can suddenly break apart and collapse.

According to records, the ice avalanche took about seven minutes to reach Gyirong Port, traveling roughly 20 kilometers in that time – an extremely high speed.

The sudden ice avalanche also triggered secondary hazards and created multiple risks. But what exactly is an ice-avalanche debris flow, how destructive can it be, and what dangers could a resulting barrier lake pose?

Guo explained that glaciers moving gradually and regularly do not normally cause disasters. However, when a glacier suddenly undergoes violent movement, rapidly surges forward or collapses from a high altitude, it can mobilize accumulated glacial debris. This material then rushes down steep valleys, forming a high-speed debris flow.

Large volumes of glacial debris mixed with rocks and soil can surge rapidly downstream. With an enormous volume of material and extremely high velocity, the resulting ice-avalanche debris flow can generate tremendous impact forces.

Compared with ordinary mountain torrents or floods, such events carry greater kinetic energy and can be far more destructive, posing a serious threat to river channels and infrastructure along their path.

The combined effects of complex geological and climatic factors have made areas along the Himalayas particularly prone to geological disasters. Experts warned that climate change is continuing to increase risks associated with glaciers and glacial lakes in the region.

As glaciers continue to retreat and glacial lakes expand, experts said, the likelihood of disasters such as glacial lake outburst floods and ice avalanches is increasing.