Scientists say a flash flood in Nepal on Wednesday was likely caused by a large piece of a glacier breaking off.

This piece may have blocked a river for a short time.

The water that built up behind it may have then rushed downstream with great force.

The flood killed at least 353 people.

More than 1,300 people are still missing.

The U.S. Geological Survey reported a glacier collapse with a magnitude of 5.2.

This report is based on seismic data and satellite images.

Jakob Steiner, a geoscientist at the University of Graz, said the lower part of a glacier fell off.

He added that the falling ice may have felt like a bomb exploding.

Researchers said it is too early to link the disaster directly to global warming.

But they noted that rising temperatures make such events more likely.

This is especially true in the Himalayas, which are warming faster than many other areas.

Water levels in affected rivers rose by up to 9 meters in 30 minutes.

The Hindu Kush Himalaya holds the largest amount of snow and ice outside the polar regions.

About 78% of its glacier area is highly exposed to warming.

Scientists say melting glaciers can make glacial lakes bigger and weaken mountain slopes.

This raises the risk of sudden floods and other dangers.

Steiner said the area has a history of destructive mountain events, including floods and avalanches.

He warned that what happened is "the new normal" and that risks will grow.

Experts call for better early warning systems and faster sharing of information.

But they say watching thousands of glaciers is very hard, leaving only minutes to act in some cases.