The devastating floods that struck Nepal’s border with Tibet have raised concerns in India, where several major rivers originating in Nepal flow into the northern plains. Experts say the disaster is a warning not simply because floodwaters cross the border, but because India and Nepal share an increasingly volatile Himalayan river system.
Nepal has more than 6,000 rivers and streams, most of which drain southwards into India and eventually the Ganges. The Kosi, Gandaki, Karnali and Mahakali are among the major transboundary river systems, while smaller rivers such as the Bagmati, Kamala, Rapti and Babai can produce rapid and unpredictable floods.
Bihar faces the greatest exposure. Nearly three quarters of north Bihar is classified as flood prone with major rivers including the Kosi, Gandak, Bagmati and Kamala originating in Nepal. Eastern Uttar Pradesh is also vulnerable to flooding from the Ghaghara, Rapti and Gandak, while parts of Uttarakhand and West Bengal face risks from other transboundary rivers.
However, experts caution against viewing floods in India as simply a consequence of Nepal “releasing” water. Nepal has very limited reservoir capacity, and the major Kosi and Gandak barrages are operated by India. The amount of water reaching the Indian plains is largely determined by rainfall upstream.
The severity of flooding after the water reaches India, however, depends heavily on conditions within India itself. Rainfall on the Indian side, river levels, embankments, barrages, drainage systems, sediment accumulation and development on floodplains can all determine whether a high river flow becomes a disaster.
The 2008 Kosi disaster illustrates the point. Nearly 400 people died after the river breached an embankment, even though the river’s flow was reportedly well below its carrying capacity. Experts described the failure as structural rather than hydrological, with poorly maintained embankments developing vulnerable points.
India and Nepal already exchange real time rainfall and river level information through monitoring stations, with Nepal’s Department of Hydrology and Meteorology providing data to India’s Central Water Commission for flood forecasting.
But significant gaps remain. Experts point to inadequate real time monitoring in some of the fastest flowing Chure catchments, the absence of a common forecasting model and limited routine sharing of information about embankment conditions river channel changes and sediment.
For conventional monsoon floods, India can sometimes receive between roughly 12 hours and two days of warning. But flash floods from smaller Chure rivers can reach downstream areas within hours.
The warning window can become even shorter when a landslide dam burst or debris flow occurs. In the latest Nepal disaster, the peak surge reportedly reached Triveni near the Indian border in about seven and a half hours.
Experts say that receiving a warning at a government office is not enough. The information must reach communities quickly and clearly enough for people to evacuate.
The bigger threat is not a conventional flood
Experts say the most important lesson for India is that the latest Nepal disaster was not simply a normal river flood.
In the high Himalayas, intense rainfall, melting ice, unstable rocks, glaciers and enormous quantities of sediment can combine to create extremely powerful debris flows. Such events can move rapidly and destroy infrastructure far beyond what would be expected from a conventional flood.
India has already experienced similar disasters, including the 2021 Chamoli disaster in Uttarakhand and the 2025 Dharali flash flood. The latest Nepal event has been described by experts as potentially several times larger than those incidents.
Climate change is adding to these risks. Rising temperatures are accelerating glacier retreat and degrading permafrost, while a warmer atmosphere can hold more moisture and contribute to heavier bursts of rainfall. These changes can increase the likelihood of landslides, glacial hazards and sediment heavy floods.
More extreme events can also increase sediment deposition in rivers, raising riverbeds and reducing the capacity of channels to carry water safely.
India and Nepal need stronger cooperation
Experts say the answer cannot be limited to blaming either country. Nepal rainfall can strongly influence the timing and size of flood peaks entering India, while conditions in India determine how severe the resulting flooding becomes.
The two countries therefore need stronger cooperation on real time data, river forecasting, embankment monitoring, sediment management and early warning systems.
Continuous monitoring of glaciers and glacial lakes, improved satellite observations and faster communication with communities could also help reduce risks.
The Nepal floods are ultimately a warning about a shared Himalayan hazard system. As climate change makes extreme rainfall, glacier instability and other mountain hazards more unpredictable, India’s preparedness will increasingly depend not only on managing rivers after they reach the plains but on understanding and monitoring the rapidly changing mountains where those risks begin.