Emergency warnings weren’t enough to save Nepal’s flood-ravaged villages. An expert explains

A flash flood can transform a river within minutes.

This is what communities near the Nepal-Tibet border witnessed on Wednesday .

A massive flash flood ripped through villages along the Bhote Koshi–Trishuli river system carrying mud, debris and fast-flowing water.

It has claimed the lives of at least 469 people and left hundreds more missing, including 39 Australians .

Preliminary investigations suggest the flood was caused by a major collapse of ice and rock high in the Himalayas.

During such disasters, every extra minute is valuable time to reach higher ground.

So how can we ensure communities are prepared in the face of such rapidly developing hazards? Our research suggests early warning systems may help.

How do early warning systems work? Early warning systems use various tools, data and communication channels to detect natural disasters before they strike.

These systems do much more than send a text message after a flood or fire has started.

They are designed to identify a potential hazard early, track it as it develops, and forecast where it may go.

The most effective early warning systems communicate this information quickly, enabling the public and emergency responders to act.

These systems have saved lives.

In the Swiss village of Blatten, monitoring enabled authorities to evacuate residents before a massive rock-ice avalanche swept through the region in 2025.

In Iceland, monitoring and established emergency procedures allowed more than 800 people to escape sudden glacial floods during the 2010 Eyjafjallajökull eruption .