Bhutan lake breach sends flood warning toward Assam and Bengal
Cross-border flood risks expose gaps in Himalayan early-warning systems
Overview
A sudden breach at Bhutan’s sent floodwater into the and river areas. The water damaged the road to remote Laya, triggered warning sirens and pushed people toward safer ground. Reports estimate that about 7.4 million cubic metres of water escaped, but the full scale was initially unclear. Water reached the , where all sluice gates were reportedly opened. Bhutan’s hydrology agency continued tracking river levels.
After entering India, the river becomes the . The surge could reach the border within six to eight hours. India issued a special warning for Alipurduar, Cooch Behar and Dhubri, while gauges and officials watched for sudden rises. The flood’s peak, debris, flooded areas and downstream damage remain uncertain, leaving riverside residents at risk even though no major impacts have yet been confirmed.
Timeline
Bhutan and India continued assessing the surge while downstream damage remained unclear
Bhutanese hydrology officials continued tracking water levels, while Indian authorities monitored the Sankosh River and vulnerable districts. Early reports did not establish the flood's peak, , final inundation or downstream damage. The initial assessment also said that no alert had yet been triggered at the when the first reports emerged, leaving uncertainty about the warning timeline.
Authorities ordered monitoring at Sankosh river gauges in West Bengal and Assam
Officials instructed monitoring teams at Barobisha, Sankosh LRP, Golakganj and Baladoba to watch river levels and report significant changes. The alerts followed the water's expected path from the Mo Chhu and Punatsangchhu catchments into the . District administrations were asked to maintain precautionary measures around vulnerable riverbanks and settlements.
West Bengal warned Sankosh communities in Alipurduar and Cooch Behar
West Bengal authorities urged residents near the Sankosh River to remain vigilant and move to safer locations if necessary. Warnings covered Kumargram, , Kumargram forest village, Pakriguri, Bholka, Changmari and adjoining areas. Alipurduar and Cooch Behar administrations were directed to monitor river conditions and prepare for possible flooding.
India issued a special advisory for downstream Assam and West Bengal
Indian authorities warned that the flash flood from the could sharply raise water levels in the . The advisory identified West Bengal's Alipurduar district and Assam's Dhubri district as vulnerable downstream areas. Authorities estimated that the surge could reach the India-Bhutan border within six to eight hours.
Floodwater reportedly reached the PHPA-II dam area as sluice gates were opened
Reports said floodwater reached the area and that all were opened. The same reports said the reservoir was empty and that water was expected to reach the Puna-I dam area within roughly 10 to 15 minutes, but these operational details were not independently confirmed.
Bhutan sounded sirens and moved people away from the Mo Chhu and Punatsangchhu rivers
Sirens were activated near the Mo Chhu and downstream as authorities warned riverside communities about the sudden surge. Residents and personnel in vulnerable locations were reportedly moved to safer ground. Bhutan's began monitoring water levels at stations including Taktsemakhang, Tashithang and Yebesa.
Floodwater crossed Taktsemakhang and damaged access to Bhutan's Laya region
The surge reached Taktsemakhang at about 8:15 to 8:27 p.m., according to reports. Floodwater damaged part of the and made the route impassable, cutting off the remote Laya region. No casualties were reported in the initial accounts.
Shintaphu Lake reportedly breached below Wakila Mountain in Bhutan
A was reported Thursday evening at Shintaphu Lake below Wakila Mountain in Lungo, Laya Gewog, Gasa district. The lake is in Bhutan's , which connects downstream to the Sankosh river system. Reports said the volume released could not yet be assessed, so the reported 7.4 million cubic metres remained unconfirmed.