A tourist filming the mountainous landscape in Gyirong County in China’s Xizang Autonomous Region accidentally captured what experts believe was the high-altitude glacier collapse that triggered the deadly mudslide at Gyirong Port on the Nepal-China border.

According to a China Xinhua News report, Kang Shichang, director of the Institute of Mountain Hazards and Environment under the Chinese Academy of Sciences, confirmed that the location visible in the video corresponds with the area identified in remote-sensing imagery as the source of the disaster.

The footage is believed to show the glacier collapse on the Nepalese side that set off the chain of events leading to the mudslide at Gyirong Port, the report said.

A tourist filming the scenery in Gyirong County, China’s Xizang Autonomous Region, accidentally captured the moment of a high-altitude glacier collapse in Nepal.

Kang Shichang, director of the Institute of Mountain Hazards and...