Nepal issued a fresh flood alert on Thursday after China warned that a newly formed lake upstream of the Lhende River could burst and send another surge of water towards areas already devastated by Wednesday’s catastrophic flooding.
Nepal’s National Disaster Risk Reduction and Management Authority (NDRRMA) asked residents, travellers and rescue teams in vulnerable downstream areas to remain on high alert and stay away from riverbanks following information received from the Chinese side. The warning concerns an obstruction in the upper reaches of the river system near the Nepal-China border. Debris has blocked the flow of water at or near the area from where Wednesday’s destructive surge originated, creating a temporary lake behind the obstruction.
Preliminary examination of satellite imagery indicates that water is continuing to accumulate in the lake, raising fears that the natural barrier could fail suddenly. Such a breach could release a large volume of water into the Bhote Koshi system with little warning.
Nepal’s Department of Hydrology and Meteorology issued a special notice after receiving information from China through the Ministry of Foreign Affairs. The Flood Forecasting Division said people in downstream settlements should remain in safer locations until the threat subsides.
Downstream areas on alert
Authorities have specifically cautioned people living along the Bhote Koshi corridor, as well as passengers and emergency personnel operating near the river.
Rescue teams are still working across areas devastated by Wednesday’s flood, making the possibility of another sudden surge particularly dangerous. Damaged roads, bridges and communications have already complicated access to several affected locations.
The NDRRMA advised people not to approach the river to observe changing water levels and asked those involved in rescue and relief operations to remain aware of the possibility of a rapid rise.
Wednesday’s flood struck Nepal’s Rasuwa district after a huge volume of water, mud and debris rushed downstream from the Tibet side of the border. Settlements, roads, security installations and hydropower infrastructure were among the areas affected.
The Bhote Koshi eventually joins the Trishuli river system, meaning a major upstream release could have consequences well beyond communities immediately adjoining the border.
Satellite images reveal blockage
Early assessments of Wednesday’s disaster indicate that an ice avalanche or snow-and-rock collapse may have played a central role.
Satellite imagery obtained from Chinese authorities showed debris blocking the Lhende River roughly 20 kilometres upstream of the Miteri Bridge. Water accumulated behind that obstruction before a sudden release swept downstream, according to Nepal’s hydrology officials.
Investigators are still establishing the precise sequence of events, but officials have been examining whether the catastrophe involved a glacial or debris-dammed lake outburst rather than being driven principally by rainfall.
The latest lake formation has heightened those concerns because unstable accumulations of rock, ice and sediment can act as temporary dams in high-altitude valleys. As water builds behind them, the pressure can eventually overwhelm the barrier and produce a sudden flood.
Fresh threat complicates rescue work
The renewed warning comes while Nepal and China are still searching for people missing after Wednesday’s disaster. The possibility of another outburst poses an immediate challenge to rescue workers operating close to waterways and unstable slopes.
China is also dealing with a separate barrier-lake threat on its side of the border. Authorities have warned that millions of cubic metres of additional water could enter an already dammed lake over the coming days, increasing the danger of another breach.
Forecast rainfall could further complicate conditions across the Himalayan border region, where unstable slopes and debris left by the initial disaster remain vulnerable to fresh movement.
For Nepal, the immediate priority is keeping downstream communities and rescue personnel away from exposed areas while authorities track the expanding lake and assess whether the debris barrier holding back the water remains stable.