Glacial lake outburst in Bhutan triggers flood alert in northern West Bengal, Assam

Map shows Glacial lakes in Bhutan. Image used for representational purposes only. Photo: Special Arrangements A glacial lake outburst flood (GLOF) in Bhutan has triggered a high flood alert in parts of northern West Bengal, prompting evacuations in areas along the Sankosh River and its tributaries amid fears of a sudden rise in water levels, officials said on Friday (October 30, 2026).

Residents of riverbank villages in Alipurduar district were seen leaving their homes with their cattle after the administration issued evacuation instructions. Water Resources Investigation and Development Minister Nisith Pramanik said a glacial outburst had occurred at Lemthang in Bhutan, with water from the lake flowing through the Mo (Mofu) River towards the Sankosh.

“Everyone living in the catchment areas of the Sankosh River and all its connected tributaries has been asked to move to a safe distance immediately to protect their lives,” Mr. Pramanik said in a video message. He urged residents living near riverbeds in Tufanganj and adjoining areas in Cooch Behar to evacuate immediately in view of the potential flooding.

He said the administration was prepared to deal with any eventuality, with teams of the State Disaster Response Force (SDRF) and the National Disaster Response Force (NDRF) kept on alert for rescue and relief operations.

Darjeeling MP Raju Bista urged people in the Darjeeling hills, Terai and Dooars regions to remain vigilant and follow official advisories. Nearly 7.4 million cubic metres of water had surged out of the breached Shintaphu Lake in Bhutan into the Mo River, raising fears of a sudden increase in the water level of the Sankosh, which flows along the West Bengal-Assam border.

“The administration began evacuation measures late Thursday night (October 29) in villages along the Sankosh. Loudspeaker announcements were made in riverbank settlements under the Rampur-I gram panchayat area, asking residents to leave their homes and move to designated shelters,” officials said.

The surge could reach border areas within six to eight hours, potentially inundating vulnerable settlements in West Bengal and Assam, they said. The IMD has also forecast heavy rainfall in Alipurduar on Friday (October 30) , which could further complicate the situation.

The developments have also raised concerns over the Punatsangchhu project, a major India-Bhutan joint venture, as a sudden and substantial rise in river levels could pose a threat to hydropower infrastructure. A special advisory issued by the Union Ministry of Jal Shakti on Thursday (October 29) for Assam and West Bengal said the Indian Embassy had reported a GLOF in Shintaphu Lake in Bhutan’s Punatsangchhu river basin.

Following reports of flash floods in the river’s upper reaches, water levels in the Sankosh could rise suddenly in Assam’s Dhubri and West Bengal’s Alipurduar districts, the advisory said. Local authorities in the two districts have been asked to remain alert, closely monitor the situation and take necessary precautionary measures, it added.

The Assam government was closely monitoring the situation following a Glacial Lake Outburst Flood (GLOF) in neighbouring Bhutan, with Dhubri district put on alert for possible downstream effects, officials said on Friday (October 30).

The Sankosh River, which flows through Dhubri district, could be affected by the flood, prompting authorities to step up vigilance and prepare for a possible rise in water levels, they said.