“India should be worried, but not necessarily about the Kosi River in Nepal,” says Rajeev Sinha.
In other words, according to experts, the real warning is about what happens in the Himalayas, and what happens when water, rocks, ice and massive amounts of sediment suddenly come together.
Sinha says the latest disaster in Nepal is reminiscent of a series of catastrophic events India has experienced in recent years, including the Chamoli disaster in 2021 and the Dharali disaster in Uttarakhand in 2025. The event in Nepal was “perhaps five to ten times larger,” he said.
“The key point is that these are not ordinary hydrological floods,” Sinha says.
A normal flood is mostly water. But when water from heavy rain, melting ice or a sudden discharge mixes with massive amounts of sediment, the result can be a thick, high-energy slurry that can destroy almost anything in its path.
That was the lesson of the 2021 Chamoli disaster, when a large part of a Himalayan glacier collapsed in the Chamoli Valley in northern India, sending a cascade of debris and water downstream that killed 200 people and damaged hydropower infrastructure.
This was also evident in Dharali in Uttarakhand in 2025, after heavy rains caused flash flooding and a torrent of debris buried parts of the village under meters of material.
And then climate change happens.
Extreme precipitation is on the rise, with the region warming faster than the global average, a warmer atmosphere holding more moisture and monsoons bringing more rain with fewer and stronger gusts, experts say.
Alpine dangers are also growing. As permafrost degrades, glacial lake outbursts and rock-ice avalanches are expected to increase, leading to faster debris floods that are more difficult to predict.
And more extreme events mean more landslides and sedimentation in rivers, rising river beds and reduced capacity of canals on both sides of the border.
They are manifestations of the same broad Himalayan hazard system. And India’s exposure is significant.