[Anchor]

As you saw earlier, this mega-flood struck suddenly without a drop of rain, and its destructive power was far greater than that of a flood caused by heavy rainfall.

How did such a glacial flood occur, and what is the extent of the additional risk? Reporter Seo Donggyun will explain in detail.

[Reporter]

Ice in high-altitude regions like the Himalayas forms when more snow accumulates than melts.

However, over the past 30 years, temperatures in Nepal have risen rapidly by 0.02 to 0.16 degrees Celsius annually depending on the region.

Naturally, the area covered by glaciers has decreased.

They have been disappearing at a rate of 1 to 5 square kilometers every year.

When glaciers collapse, floods can occur in broadly two ways.

First, when a massive glacier breaks off, the ice and rocks swept down with it can block a river, creating a natural dam.

As water builds up, this dam can suddenly collapse, leading to a flood.

Weight is being given to the possibility that Nepal's recent mega-flood occurred in this manner.

There is another possibility.

Lakes formed by accumulated meltwater from glaciers are called glacial lakes, and when these glacial lakes suffer external impacts and collapse, they can also trigger flash floods.

According to recent studies, 189 floods of this type have occurred in the Himalayas since 1900, killing some 6,600 people.

The danger is growing steadily.

Over the past 30 years, the area of Himalayan glacial lakes has increased by 0.83% annually, and their number reaches around 2,000.

An analysis of about 550 glacial lakes in the border region between China and Nepal showed that 26% are at high risk of collapse, according to research results.

Glacier collapses can lead to even faster glacier collapses.

[Kim Baek-min / Professor, Department of Environmental Atmospheric Sciences, Pukyong National University : Because snow melts due to global warming, the effect of white snow reflecting sunlight diminishes, which accelerates global warming by two or three times.]

While it is premature to conclude that climate change is the cause of this mega-flood, it is clear that climate change is increasing potential flood risks.

(Video Editing: Lee Sang-min, Design: Park Chun-woong, Park Tae-young)