[Anchor]

A massive torrent of water triggered by a glacial avalanche swallowed everything in its path created by humans. Now, warnings are emerging that a secondary catastrophic flood could occur locally.

Reporter Choi Go-un has the details.

[Reporter]

A border checkpoint connecting Nepal and China.

A massive wall of mud completely swallows an entire building whole.

A parking lot building where dozens of buses were gathered is instantly crushed as if it were a toy.

Nothing could withstand the muddy tsunami that swept down the gorge at a high speed accompanied by a deafening roar.

[Flood Witness: It felt like the current was flowing at 20 meters per second. The flood struck in such a short amount of time that the chances of escaping were extremely low.]

Despite the clear weather with no heavy rain, the cause of the massive flood is pointed to as a glacial collapse.

In the high-altitude border region between Nepal and China, the impact of climate change caused a massive amount of glaciers and rocks to collapse, blocking the river's flow. The temporary "glacial dam" formed in this way could no longer hold and suddenly collapsed, causing a tremendous amount of water and sediment to pour downstream all at once.

The tremors initially observed as an earthquake by the U.S. Geological Survey were also revealed to be a seismic-like phenomenon generated by the collapse of the glacier and rock masses.

[Tang Chuan / Chengdu University of Technology Institute of Geohazards Prevention: A waterfall-like mixture of glaciers and rocks poured down along the major valley, eroding rocks along the path and triggering a massive debris flow, resulting in a large-scale disaster.]

An even bigger problem is the risk of a secondary flood.

Aerial footage filmed today (the 27th) clearly shows the debris blocking the river in the upstream area where the flood first began.

The thickness of the debris flow at the edges reaches up to 1.5 meters, making it a massive scale that cannot be easily removed.

[Chinese State Media CCTV Reporter: It has started to rain, and the aircraft is soaked. Despite the difficult situation, we are maintaining low-altitude flight and heading to the disaster area.]

Concerns are rising that if water continues to accumulate in the section, it may not withstand the pressure and collapse again, dealing a severe blow to the already difficult rescue and recovery operations.

(Video Editing: Wei Yuanyang, Design: Seo Seung-hyun)