Authorities in Uttar Pradesh, Bihar, and Uttarakhand were put on high alert after a sudden flash flood in neighbouring Nepal swept through mountain valleys, killing dozens of people and leaving nearly 400 tourists, including 105 Indians, missing.
The flash flood about 200 km north of the India border may result in water levels rising in rivers flowing from Nepal, such as the Gandak in Uttar Pradesh and parts of north Bihar. Trishuli river, which takes in most of the Bhote Koshi river that originates from Tibet, flows into the Gandak.
Heavy rain and the opening of barrage gates in Nepal could also increase flow into the Ghaghara and Rapti rivers in Uttar Pradesh and the Kosi in Bihar.
Deep Dive
What triggered the flash floods in Nepal that affected border districts of India?
How are authorities in Uttar Pradesh and Bihar responding to the flash floods in Nepal?
Why is there a potential for rising water levels in the Gandak and Narayani rivers?
Citing an advisory from India’s Central Water Commission (CWC), the National Disaster Response Force (NDRF) said the deluge was triggered upstream in Nepal’s mountainous Rasuwa district due to a suspected glacial lake outburst flood (GLOF). In a statement, NDRF said districts in Bihar and Uttar Pradesh near the India–Nepal border along the Gandak river have been advised to remain alert and closely monitor the situation.
Flash floods in Himalayan rivers, triggered by factors such as earthquakes or GLOFs, are not uncommon. According to an analysis by the International Centre for Integrated Mountain Development (ICIMOD) in February 2025, at least 1,015 flood events were reported in the higher reaches of the Himalayan region since 1950 across Nepal, India and China.
{{/usCountry}}Flash floods in Himalayan rivers, triggered by factors such as earthquakes or GLOFs, are not uncommon. According to an analysis by the International Centre for Integrated Mountain Development (ICIMOD) in February 2025, at least 1,015 flood events were reported in the higher reaches of the Himalayan region since 1950 across Nepal, India and China.
{{/usCountry}}In Bihar, the government has ordered the evacuation of people living in low-lying areas in five districts -- West Champaran, East Champaran, Gopalganj, Sapaul and Muzaffarpur -- as thousands of cusecs of additional water are expected to flow.
At 5pm, the discharge from Valmikinagar barrage was 1.06 lakh cusecs. Officials said it may increase to three lakh cusecs by Thursday morning. As a precaution, all 36 gates of the Valmikinagar barrage (designed capacity 8.5 lakh cusecs) were opened in phases, government officials said.
“We are expecting about 300,000 cusecs of water at the Valmikinagar barrage in the next five-six hours,” said Iqbal Anwar, executive engineer at Valmikinagar.
West Champaran magistrate Taranjot Singh said all field formations have been activated in wake of rising water levels at Devghat in Nepal, about 80 km from Valmikinagar. At the Devghat gauge site on the Narayani in Nepal, the water level stood at 4.77 metres—well below the warning level of 7.30 metres and the danger mark of nine metres. Discharge at the barrage rose steadily through the day from around 86,000 cusecs in the morning to about 1,44,800 cusecs by 4 pm.
Bihar chief minister Samrat Choudhary said a close watch was being kept on the Gandak river. A high-level committee comprising the chief secretary and the Director General of Police has been formed to monitor the situation. “If necessary, I will also visit Valmiki Nagar to assess the situation,” he said in Patna.
Union home minister Amit Shah also spoke with Choudhary in this context and promised to extend all assistance needed by the state to deal with the potential crisis.
Teams of the NDRF and the State Disaster Response Force (SDRF) have been deployed near vulnerable zones.
Gopalganj district magistrate Sameer Saurabh said a 30-member NDRF team and SDRF units were stationed at Chawahi near Gopalganj to evacuate families from low-lying areas. West Champaran District Magistrate Taranjot Singh said all field formations were activated following rising water levels at Devghat in Nepal, about 80km from Valmikinagar.
“We are expecting about 300,000 cusecs of water at Valmikinagar barrage in the next five to six hours. As precautionary measures, all 36 gates of the Gandak barrage are being opened in a phased manner. Supply of water into the canal is being disrupted,” said Iqbal Anwar, an executive engineer in Valmikinagar.
The Uttar Pradesh government has sounded an alert in Maharajganj and Kushinagar districts bordering Nepal. UP Chief Minister Yogi Adityanath directed the local administration in the two districts to ensure all necessary preparedness measures saying that water levels in Gandak and Narayani rivers in Maharajganj and Kushinagar may rise due to the flooding in Nepal.
Officials of Uttarakhand Disaster Management Authority said that officials in border districts such as Chamoli have been briefed about the Nepal floods. “The impact on Uttarakhand rivers is unlikely as most of the Kosi river system water flows into Uttar Pradesh and Bihar rivers,” a senior official said.
(With inputs from bureaus in Lucknow and Dehradun)