Guwahati: Flash floods in Nepal’s Rasuwa district near the Tibet border have killed at least nine people and left several others missing, according to officials.

The flooding on Wednesday swept away houses, vehicles, bridges and sites of infrastructure projects. Bihar, which shares a border with Nepal, also issued an alert as floodwaters moved downstream.

Officials said floodwater entered the Bhote Koshi River from the Tibetan side at around 9 am and caused major damage in Timure and Syapru Besi.

A mudslide was also reported near the Gyirong border crossing on the Tibetan side, where people were killed and others went missing, according to China’s state-run Xinhua.

The reason for the sudden flooding has not yet been established. Nepal’s Flood Forecasting Division said heavy rainfall in Rasuwa was unlikely to have triggered the event, while satellite images indicated substantial rain on the Tibetan side.

Authorities are examining whether a glacial lake outburst flood (GLOF) may have caused the surge, The Kathmandu Post reported.

Footage shared on social media showed swollen rivers rushing through the area, including a bridge being carried away by floodwater. Another video showed a house collapsing while people nearby screamed and fled.

The Nepal government launched rescue efforts in the affected areas. Helicopters, however, could not land at locations where water levels remained too high. In Tibet, Chinese President Xi Jinping ordered intensified searches for missing people and called for improved monitoring and early-warning measures to reduce the risk of further disasters.

In neighbouring India, the Bihar government increased monitoring of the situation in Nepal. Chief Secretary Pratyaya Amrit held a video conference with district magistrates and instructed officials in districts along the Gandak and Kosi river systems to remain especially vigilant.

Rasuwa Chief District Officer Narendra Pariyar said authorities had received information about villages and infrastructure sites being swept away, although the full extent of the destruction was not immediately known, Reuters reported.

Pariyar warned that the flooding could have caused significant loss of life and property.

Timure Bazaar, located close to the Tibet border, suffered extensive damage along with the nearby customs area. Local officials said vehicles and goods were carried away by the floodwaters. The Friendship Bridge at Rasuwagadhi, which had been rebuilt after a deadly flood last year, was also destroyed.

Nepal Police said three of its facilities were damaged: the Area Police Office in Timure, the Police Post in Syaphrubesi and the Police Post at Rasuwagadhi. Nine Armed Police Force personnel stationed in Timure near the Tibet border were also reported missing, The Kathmandu Post reported.

Several hydropower facilities, roads and bridges were damaged or swept away. Nepal’s Energy Ministry said about 430 MW of electricity generation capacity was affected, mainly at hydropower projects. This represents more than 12 per cent of Nepal’s total installed hydropower capacity of 3.2 GW, Reuters reported.

Prime Minister Balendra Shah held an emergency Council of Ministers meeting to assess the flood situation, the damage caused and ongoing rescue operations. Police, the Nepal Army and the Armed Police Force were deployed to search for missing people and carry out rescue work. Two Army helicopters were also sent towards the affected areas, according to The Kathmandu Post.

Difficult conditions have affected the rescue effort. Army spokesperson Raja Ram Basnet said helicopters could not land at Syapru Besi and Timure because of the high water levels.

Shah directed officials to shift residents of low-lying areas to safer locations. He also urged people living near the river to remain cautious and alert.

The floodwaters subsequently travelled into the Trishuli river basin, leading to alerts in Nuwakot, Dhading, Gorkha and Chitwan. Authorities also suspended traffic from Kathmandu towards Rasuwa, Nuwakot, Chitwan and Dhading because of the flood threat, The Kathmandu Post reported.

Home Minister Sudan Gurung urged people living along the Bhote Koshi and Trishuli riverbanks to move to safer places.

The river rises in Tibet and passes through Nepal before becoming part of the Trishuli river system, which eventually flows into India as the Gandak. The area was hit by another severe flood last year, resulting in nine deaths and leaving 24 people unaccounted for.

Floodwaters also destroyed a bridge between Nepal and China, causing trade and transportation links to remain disrupted for months.

A regional climate monitoring body later attributed that flooding to the emptying of a supraglacial lake in Tibet.