A glacial lake outburst flood (GLOF) in Bhutan has triggered concerns in India, with authorities issuing flood warnings in parts of Assam and West Bengal over a possible rise in the Sankosh River. Rescue and disaster response teams have been deployed in vulnerable areas as officials monitor the movement of floodwater.

The outburst was reported on Thursday evening at Shintaphu Lake, also known as Shintaphu Tsho, below Wakila Mountain in Bhutan’s Gasa district. The lake is located in the upper reaches of the Mo Chhu river basin, which forms part of the Punatsangchhu basin. The river is known as the Sankosh after entering India.

Glacial lake outburst flood in Bhutan

#WATCH | Alipurduar, West Bengal: On the preparedness for the effect of a Glacial Lake Outburst Flood (GLOF) at Shintaphu Lake in Bhutan, SP Amit Kumar Shaw said, “First of all, I would like to tell the residents of the district that there is absolutely no need to panic. The situation is currently under control. We are in constant touch with the authorities in Bhutan. Our police team, the District Magistrate (DM) and the Block Development Officer (BDO) with their respective teams, along with all relevant agencies and stakeholders are working together in close coordination. Our SDRF team is present, and an NDRF team is also on its way. A Civil Defence team is also deployed. We have already moved approximately 4,000 to 5,000 people into shelters, utilizing school buildings as relief centers. Additionally, more than 6,000 people have been relocated to safe areas…based on the current flow of water—and the latest information we have received—the intensity has decreased slightly, but we remain on high alert…the police, the DM’s office, and the BDO’s office have made arrangements for dry food and drinking water. We have also ensured that other necessities, such as toilet facilities, are provided. We will wait to see what the situation looks like in two hours. We are fully prepared and ready to handle any emergency that may arise. A red alert is currently in effect for the Sankosh river system…over the next few hours, we expect to see water flowing through the Sankosh River, likely accompanied by dead fish, as well as large pieces of wood and concrete debris…”

— ANI (@ANI) October 30, 2026

The flash flood partially damaged a solar-powered irrigation system in Dochhukha-Dzomlingthang-Ritsa Chiwog, under Guma Gewog in Punakha. The facility, installed earlier this year to address local water shortages, has stopped functioning. The full extent of the damage is yet to be assessed.

Floodwater also swept debris onto a section of the Punakha-Gasa Highway near Dzomlingthang. No casualties have been reported so far.

Shintaphu Lake is among Bhutan’s 17 glacial lakes identified as potentially dangerous. An official from the National Centre for Hydrology and Meteorology said a water-level monitoring station was operating at Taktsimakhang, but it had not triggered an alert when the initial reports emerged. The extent of the outburst and its impact downstream remained unclear.

GLOF: Flood warnings in Assam, West Bengal

The Centre issued an advisory warning of a possible sudden rise in the Sankosh River. West Bengal’s Alipurduar district and Assam’s Dhubri district are among the areas facing a potential threat.

Alerts have also been issued in parts of North Bengal, including the Darjeeling hills, Jalpaiguri and Cooch Behar. NDRF and SDRF teams have been deployed in Tufanganj and Boxirhat in Cooch Behar, both located near the Sankosh River and the Assam border.

The advisory warned that floodwater could reach the India-Bhutan border within six to eight hours. District authorities have been asked to monitor river levels and take necessary precautions.

Red alert for Sankosh river system

Alipurduar, West Bengal: District administration and police remain on alert amid fears of flooding as residents living near the Sankosh River and other rivers express concern over possible water inflows from Bhutan,

SP Amit Kumar Shaw says, “People are slightly in panic, and my appeal to everyone is that there is no need to panic in any way. We are in alert mode, the administration is fully prompt, and all agencies are actively working, so there is no issue. We hope that within two to three hours, we will reach a resolution and address whatever trouble the public is facing…”

— IANS (@ians_india) October 30, 2026

Superintendent of Police Amit Kumar Shaw said around 4,000 to 5,000 people had been shifted to shelters set up in school buildings, while over 6,000 others had been relocated to safe areas. SDRF, police and Civil Defence teams are deployed, while an NDRF team is on its way. Dry food, drinking water and toilet facilities have also been arranged.

Shaw said the intensity of the water flow had reduced slightly, but a red alert remained in place for the Sankosh river system. He urged residents not to panic, saying all agencies were coordinating closely.

West Bengal Forest Minister and Kumargram MLA Manoj Kumar Oraon appealed to people living along the Sankosh in Alipurduar to move to safer places. In a video message, he warned that a surge could reach Kumargram within the next one to one-and-a-half hours.

Darjeeling BJP MP Raju Bista also issued a public safety appeal, asking residents in areas along the Sankosh and its tributaries to relocate immediately.

“Everyone in our Darjeeling hills, Terai and Dooars region are requested to stay alert,” he said in a post on X.

What is GLOF?

A glacial lake outburst flood occurs when water stored in a lake formed by melting glaciers is suddenly released, usually after the natural barrier holding it back breaks or gives way.

The resulting flood can travel quickly through mountain valleys, carrying rocks and debris. It can damage homes, roads, bridges, farmland and other infrastructure. Since the Sankosh flows from Bhutan into India, a sudden increase in its water level could affect riverside communities in both West Bengal and Assam.