[Anchor]

The sudden disaster that struck the border between Nepal and China's Tibet was triggered when a massive chunk of a glacier broke off in the Himalayas. A staggering 20 billion liters of a water bomb cascaded down the gorge, with the water level at the time estimated to have reached 50 meters.

Reporter Kwon Min-kyu has the details.

[Reporter]

This catastrophic flood began in the high-altitude Himalayan region of the Rasuwa district in northern Nepal.

According to an analysis of satellite imagery by a research team at the University of Calgary in Canada, the glacier collapse occurred at an altitude of 5,000 meters above sea level.

The width of the detached glacier is estimated to be approximately 600 meters.

The glacial mass plummeted 1,200 meters, dragging down rocks and soil from the mountain along with it.

It initially blocked the river stream midway up the mountain, but the heat and impact from the collapsing glacier and rocks caused the ice to melt even more rapidly. It eventually burst open, pouring down all at once into the narrow valley.

According to the Lamont-Doherty Earth Observatory at Columbia University, the speed of the water current at the time reached 70 kilometers per hour.

The floodwater level was estimated to be a massive 50 meters.

The Nepal Flood Forecasting Division stated that the landslide unleashed 20 million cubic meters, equivalent to 20 billion liters of a water bomb, into the gorge.

That is enough amount to fill 8,000 Olympic-sized swimming pools.

The torrent generated in this manner swallowed the Rasuwagadhi border checkpoint, located 20 kilometers away from the landslide site, and swept down villages situated 60 kilometers away along the gorge.

Furthermore, experts analyze that because it was a debris flow mixed with rocks, soil, and water, it created a destructive flow carrying high energy.

The deeply carved V-shaped gorge terrain is also cited as a factor that amplified the damage.

As the torrential current concentrated into the narrow waterway, the flow velocity and water level increased further, causing water and debris to rush in even dozens of kilometers away.

Consequently, multiple villages and markets formed along the riverbanks, along with entire local areas, were swept away.

[Song Young-seok / Head of Geological Disaster Research Center, Korea Institute of Geoscience and Mineral Resources (KIGAM): If you consider a glacier width of 600 meters, imagine a dam generally about 200 to 300 meters high collapsing all at once. If you think of something like the Soyanggang Dam failing all at once, you can imagine how immense that destructive force would be.]

During the 2015 Nepal earthquake, which resulted in about 8,900 deaths, the high mountainous terrain and gorges also led to massive casualties, such as Mount Everest climbers losing their lives in avalanches.

(Video Editing: Lee Seung-yeol, Design: Lee Jun-ho, Choi Jae-young)