Building boom puts 300,000 people in the path of potential Himalayan disasters

At least 300,000 people in northern Nepal, parts of south-eastern Tibet, and a corner of India's Uttarakhand could now live in the path of potential disasters, according to a peer-reviewed study published in Scientific Reports. Researchers found built-up land in high-risk zones grew by about 45% between 2016 and 2023, rising even faster — nearly 78% — in areas threatened by glacial-lake flooding.

The team, led by University of Leeds glaciologist C Scott Watson, examined areas up to 50 km downstream from Himalayan rivers and around 1,360 glacial lakes. Development included tourism facilities, infrastructure, and real estate, much of it concentrated on low, flat land along rivers.

The findings come as Nepal's devastating August floods killed more than 1,400 people and left thousands missing, with smaller incidents including a 11 October flash flood on the Budhi Gandaki that damaged 200 houses and swept away five bridges.

Mayor Dhana Raj Acharya of Pokhara says many old buildings sit just 5 metres from river banks despite new rules requiring them further away. Homestay operator Phurpa Chhiring Lama, whose 20 rooms are usually full during peak season, now has only five occupied. Hotel Association president Laxman Subedi says tourism businesses expanded "without any proper planning" and been promoted "haphazardly".

Hydropower plants have also grown along the Bhotekoshi and Trishuli rivers. The study defines buildings at risk as those within 50 vertical metres of a river or glacial lake surface, but during the August floods some locals reported river levels rising 70 metres in places.

Risks are driven by Himalayan warming at twice the global rate, which accelerates glacier melting and expands glacial lakes — Nepal has recorded roughly 30 outburst events since 1940. Rising temperatures also push rain to higher altitudes, triggering slope failures and rock falls.

Nepal's Prime Minister Balendra Shah warned at the UN that his country pays a "colossal price" for a crisis it did not create. Authorities say they are banning settlements within 15 metres of riverbanks along the Rasuwa-Bhotekoshi corridor, though campaigners say regulations remain poorly enforced. Uttarakhand meanwhile approved new floodplain zoning rules on 12 October, but activists say construction continues unchecked.

Source: BBC Science.