Nepal flash floods trigger Gandak alert in Bihar; several districts at risk
The districts facing the most immediate risk in Bihar include West Champaran, East Champaran, Gopalganj and Saran, which are directly or closely connected to the Gandak river system. Authorities have also placed Muzaffarpur and Vaishali under heightened vigilance.
New Delhi: A massive flash flood originating from the Tibet-Nepal border on Wednesday has raised concerns over a possible surge in the Gandak river in Bihar, prompting authorities in the state to step up preparedness in the vulnerable districts.
The flash flood struck the Bhote Koshi river in Nepal’s Rasuwa district around 9am and swept away homes, roads, bridges and hydropower infrastructure. The Bhote Koshi and Trishuli rivers, key tributaries of the Narayani-Gandak river system, have witnessed sharp rises in water levels, triggering extensive damage across northern Rasuwa district in Nepal.
Media reports suggest close to 100 people have lost their lives in Nepal, with hundreds missing, including 105 Indians.
Quick answers to key questions
The flash floods in Nepal were triggered by an avalanche of ice and rock, potentially initiated by an earthquake, affecting the Bhote Koshi river and leading to significant water surges downstream.
Authorities in Bihar are concerned that the flash floods could cause a substantial rise in the Gandak river's water levels, posing a direct threat to vulnerable districts located nearby.
The IMD is monitoring the rapidly moving flood wave and potential water level increases along the Gandak river system, advising local authorities to prepare for possible evacuations and relief operations.
The districts most at risk include West Champaran, East Champaran, Gopalganj, and Saran, with additional vigilance advised for Muzaffarpur and Vaishali due to their proximity to the Gandak river system.
The Bihar government has set several districts on alert and is monitoring river levels, embankments, and low-lying areas, while also preparing evacuation and relief arrangements.
The sudden discharge has prompted high-alert advisories across downstream parts of Nepal, with people living along the Bhote Koshi, Trishuli and Narayani rivers advised to move away from riverbanks and low-lying areas.
According to the India Meteorological Department (IMD), the flood wave is moving rapidly downstream, raising concerns over rising water levels along the river system over the next 24 hours and possible impacts on downstream settlements. The development is significant for Bihar because the Narayani river enters India and becomes the Gandak, one of the major rivers flowing through north Bihar. A sudden increase in discharge in Nepal can therefore translate into a rapid rise in water levels downstream, particularly in areas close to the Gandak and its tributaries.
The Bihar government has already put several districts on alert and warned of a possible flood wave of around three metres entering the Gandak river. Authorities have directed district administrations to monitor river levels, embankments, bridges and low-lying areas and keep evacuation and relief arrangements ready.
Districts likely to be impacted
The districts facing the most immediate risk in Bihar include West Champaran, East Champaran, Gopalganj and Saran, which are directly or closely connected to the Gandak river system. Authorities have also placed Muzaffarpur and Vaishali under heightened vigilance because of the potential downstream spread of floodwaters. Sitamarhi and Sheohar have also been identified as vulnerable districts requiring preparedness, although the actual impact will depend on the volume and timing of water reaching Bihar.
West Champaran is likely to be among the first Bihar districts to experience the impact because the Gandak enters the state from Nepal through the Valmikinagar area. From there, the river flows through the northern plains towards Gopalganj, Saran and adjoining districts. A sharp rise in discharge could put pressure on embankments and low-lying settlements along the river.
According to an IMD official, the situation remains fluid because the scale of the flood wave reaching Bihar will depend on how much water is retained or dissipated as it travels through Nepal's mountainous river system. The immediate priority for downstream communities is therefore to follow official advisories, avoid riverbanks and remain prepared for rapid changes in water levels.
About the Author
Vijay C. Roy is a journalist with over 21 years of experience covering various news beats across different organisations such as Business Standard and The Tribune. In the past, he has covered beats such as finance, auto, MSME, commodities, FMCG, pharmaceutical, agriculture, IT/ITES, infrastructure and start-ups. He joined Mint in February 2025, and covers agriculture, food processing, fertilizers, environment and climate change, bringing over two decades of experience reporting on farm policy, food inflation, crop trade, and rural livelihoods.<br><br>Vijay’s areas of reporting include food security and climate change policies, focusing on their impact on different stakeholders and their implications. His expertise lies in simplifying complex agri-economic issues such as edible oil import dependence, cotton and wheat trends, fertiliser subsidies, and climate-related risks. He has covered key developments including global supply disruptions and evolving trade policies, offering both macroeconomic perspective and field-level context. Known for his credible and balanced reporting, he follows a rigorous, fact-based approach that prioritises accuracy and context. He is driven by a commitment to public interest, aiming to make critical agricultural and economic issues accessible while contributing to informed policy and industry discussions.
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