How did the Himalayan mudslides happen? What we know so far

Editor's note: Yang Zhao is the chief editor of CGTN's Sci-Tech section.

The devastating mudslides that swept through parts of Nepal and southwest China's Xizang Autonomous Region on Wednesday may have originated high in the Himalayas, with the sudden collapse of a large glacier potentially marking the beginning of a chain of cascading hazards.

But scientists caution that it is still far too early to draw definitive conclusions.

The disaster is still under investigation, and researchers are working to reconstruct exactly what happened – and what ultimately caused the ice and surrounding mountain slopes to become unstable.

What is becoming increasingly clear is that this may not have been a single event, but a series of hazards that interacted with and amplified one another.

The trigger: a glacier collapse Satellite observations, combined with preliminary analysis by Chinese geological experts, suggest that a high-altitude glacier in Nepal collapsed on Wednesday.

A large mass of ice appears to have broken apart at an elevation of more than 5,000 meters and surged down a steep mountain slope.

And it was not just ice that came down.

As the mass raced downhill, it acted like a giant bulldozer, scouring up rocks, loose sediment and other debris along the way.

What began as a glacier collapse may have rapidly transformed into a high-speed mixture of ice, rock and sediment – a process known as an ice-rock avalanche.

Huge amounts of ice and rock debris then entered a mountain river channel, picking up more water and sediment along the way.

In this way, what may have begun as a relatively localized collapse high in the mountains could have developed into a much larger disaster downstream.

Was climate change to blame? This is where scientists need to be particularly cautious.

It is too early to say that climate change directly caused this particular glacier collapse.