A torrential flash flood swept through Nepal’s Rasuwa district near the border of Tibet on the morning of August 26. Early reports suggest many residents were washed away, while houses, bridges, and other infrastructure were widely damaged.
At 9:00 am, the flash flood raced from the Tibet side into the Bhote Koshi river, causing devastation along its course.
Nepal’s energy ministry told the media that the flash flood damaged many hydropower projects. It reported that around 430 MW of electricity supply was affected—one-eighth of the country’s installed capacity.
The severity of the flash flood has generated much curiosity regarding its cause. “An initial assessment suggests that an ice avalanche blocked the Lhende river, triggering the sudden flood in the Bhote Koshi river, according to Rijan Bhakta Kayastha, a professor at Kathmandu University and climate researcher,” reports The Kathmandu Post.
According to The Kathmandu Post report, the ice avalanche blocked the Lhende river, creating a lake that ultimately burst. Kayastha was quoted in The Kathmandu Post as saying, “An earthquake also occurred on the Tibetan side around the same time.”
Last year on July 8, a flash flood was reported in the Bhote Koshi river. Nepal’s department of hydrology and meteorology attributed this flood to a glacial lake outburst.
In another post, Narendra Pariyar, Chief District Officer of Rasuwa, has been quoted as saying that there was no raining in the district headquarters. He also said that some “some natural event in the upper region” might have caused the flash flood. And it could be a glacial lake burst.
Earlier, in a study, ICIMOD stated, “The Poiqu watershed in the Tibet Autonomous Region, China, also known as the Bhote Koshi and Sun Koshi downstream in Nepal, has been identified as highly prone to glacial lakes outburst floods (GLOFs).”
China’s news agency Xinhua quoted Pariyar saying, “We cannot say for certain whether a glacial lake burst somewhere upstream or something else happened. The flood appeared suddenly."
Down To Earth reported, “In the 2000s, a glacial origin flood was expected to hit the Hindu Kush Himalaya region once every five to 10 years. However, in the last two months alone — during May and June 2025 — ICIMOD has recorded three such floods in the region: in Nepal (Limi), Afghanistan (Andorab valley) and Pakistan (Chitral, Hunza).”
“The acceleration of these types of events is completely unprecedented in the Hindu Kush Himalayan region. We need to delve deeper into the triggers that are resulting in cascading impacts,” Saswata Sanyal, ICIMOD Disaster Risk Reduction Lead, said in a statement.