Nepal's Deadly Flood: A Warning for the Himalayas?

In late August, a huge section of glacier in Nepal broke off and crashed into a river valley far below. The collapse sent waves of boulders, water, and ice rushing downstream for miles. It buried 12 power plants, destroyed dozens of bridges, and left more than 5,000 people missing. Now experts are asking whether it was safe to build so many power plants in such a dangerous mountain region.

The disaster happened on August 26 in Nepal's Rasuwa district. A glacier and the rock beneath it — stretching more than 3,800 feet wide — broke apart and fell nearly 4,000 feet into the Trishuli river valley. The waves of water, ice, and boulders reached up to 30 feet high. They swept away a multistory building, around 70 bridges, and miles of road.

About 1,400 bodies have been recovered so far, and more than 5,000 people are still missing. Among the missing are 121 workers who were inside hydropower plants when the floods hit. Rescue teams spent days just trying to find the buried plants under the mud. Arnold Dix, a tunnel expert helping with rescue efforts, said it felt like 'a bomb's gone off' — the power stations had simply disappeared under the debris.

One woman, Sumana Shrestha Amatya, stood with other families in Kathmandu, waiting for news about her husband Sunil, a geologist working at one of the plants. She has still not heard anything from officials. She called the disaster 'a Himalayan tsunami,' a phrase many Nepalis have used to describe how sudden and powerful the event was.

After the floods, experts began asking tough questions about the hydropower plants built along the Trishuli river. The river basin is home to 36 hydropower projects in total, including the 12 now buried under mud. Scientists say building so many large projects in the same valley is risky, especially in a region where earthquakes, landslides, and melting glaciers are already common. They argue that no one properly studied what could happen if many plants in the same area were hit by one disaster.

Parineeta Dandekar, a river expert, says risk studies for these projects ignored the 'cumulative disaster risk' of having so many plants on the same river. The World Bank, an international lending organization, provided about $300 million for one of the biggest plants, called the Upper Trishuli-1. That plant, which cost more than half a billion dollars to build, was still under construction when the floods hit and is now buried. Army officials estimated about 50 workers were trapped inside it.

The World Bank said its design used the best information available in 2018, when the risk study was completed. It added that it would review what the August floods mean for future hydropower projects. Another funder, the Asian Development Bank, gave $60 million for the project. Independent experts who visited the site in 2024 found that no climate resilience study had been done, and they called that a 'significant gap.'

Not everyone agrees that the power plants made the disaster worse. Engineer Dipak Gyawali said that compared to the natural forces involved, the blasting used during construction was tiny — 'like scratching your skin.' But even he agreed that developers were not doing enough to study the risks of building so many projects in the same area. 'These risks have to be properly studied and assessed. Unfortunately, they have not been,' he said.

Climate change is making the Himalayas more dangerous. Glaciers are melting faster, making mountain slopes less stable. Early studies suggest that global warming helped cause the glacier that broke off in August to become unstable. Deadly flooding has now hit the Trishuli basin three years in a row — from extreme rainfall, a glacial lake burst, and now a glacier collapse.

Nepal's disaster has brought attention to huge dam projects across the Himalayas. China and India together have built 68 major dams there, with 101 more planned. China's biggest new project, a dam in Tibet costing around $170 billion, is built near an active earthquake fault and would affect communities as far away as India. Scientists and former diplomats warn that if big construction projects keep going ahead without better safety studies, a far larger tragedy could be coming.