At least 300,000 people in parts of the Himalayas could now be living in the path of floods, a new study suggests. BBC News reports on the study, which was published in the journal Scientific Reports.

Researchers looked at northern Nepal, parts of southeastern Tibet and a corner of India's Uttarakhand state. They found that built-up land in high-risk zones near rivers grew sharply from 2016 to 2023. Near glacial lakes that could burst, building grew even faster.

The study estimates that 18 percent of people in the area, or 293,800, live within 50 vertical meters of a river channel this year. The authors say the true number could be higher, since they only looked at one area.

The study came out before deadly floods in Nepal in August, which the BBC reports left more than 1,400 dead and thousands missing. Hotels, hydropower plants, roads and homes have spread onto flat land along rivers.

In the tourist hub of Pokhara, Mayor Dhana Raj Acharya says many old buildings stand just 5 meters from riverbanks. "Where we move them, and how we do that, is the real challenge," he said. The head of a local hotel group admits tourism grew "without any proper planning."

"Development decisions being made today will shape disaster risk for decades to come," said lead author C. Scott Watson, a glaciologist at the University of Leeds.

The Himalayas are warming at twice the global rate, the BBC reports, melting glaciers and swelling glacial lakes until they burst. Nepal plans to ban homes within 15 meters of the riverbank in one hard-hit corridor. Uttarakhand approved new floodplain rules on October 12.

What we know: Building in flood-prone Himalayan valleys rose sharply from 2016 to 2023, putting about 300,000 people at risk.
What we don't: Whether new building rules will be enforced on the ground.