Explainer: What we know so far about the China-Nepal border mudslide

A mudslide originating on Nepal's side of the China-Nepal border struck the area around Gyirong Port in southwest China's Xizang Autonomous Region on August 26, leaving heavy casualties and a large number of people unaccounted for and prompting a large-scale rescue operation.

Here is what is known so far about the disaster, its causes and the ongoing response.

What happened? At around 10:30 a.m. on August 26, a mudslide on Nepal's side of the border caused heavy casualties and left a large number of people missing at Gyirong Port in Gyirong County, Xizang, according to local authorities.

As of the latest figures released by local authorities on Thursday, three people had been confirmed dead and 558 remained unaccounted for, while two local villagers had been rescued.

Among those unaccounted for were 260 foreign nationals.

The disaster disrupted roads, communications and power supplies in the area.

Authorities have evacuated residents from villages deemed at risk, while efforts are underway to restore communications and clear damaged roads.

The Chinese Foreign Ministry said Thursday that nearly 100 Chinese nationals remained unaccounted for in the affected area in Nepal.

The Chinese Embassy in Nepal is verifying the information with local authorities.

The death toll from devastating floods has risen to 359 in Nepal, as search and rescue operations continue for 910 people who are still missing, according to local authorities.

What caused the disaster? According to experts cited by Chinese authorities, the disaster was triggered by a high-elevation ice avalanche in Nepal.

The Ministry of Natural Resources said the ice avalanche generated a high-speed debris flow, which then evolved into a mudslide as it moved downstream, carrying ice, rocks and other debris.

The terrain also amplified the disaster's intensity.

According to Xu Qiang, a geological disaster expert, president of Chengdu University of Technology and chief scientist at the National Key Laboratory of Geohazard Prevention and Geoenvironment Protection, the elevation difference between the ice avalanche source area and Gyirong Port is several thousand meters.