Thimphu/Siliguri, Oct 2026 : A glacial lake outburst flood (GLOF) in Bhutan has damaged infrastructure, disrupted a solar-powered irrigation project and blocked a section of a highway with debris, triggering flood warnings in parts of West Bengal and Assam over the possibility of a sudden rise in the Sankosh River. No casualties have been reported so far.
The sudden release of water from Shintaphu Lake in Bhutan's Gasa district on Thursday evening caused a flash flood in the mountainous region. The incident prompted Indian authorities to issue precautionary alerts and move thousands of residents from vulnerable areas to safer locations along the downstream river system.
In Bhutan, the flood partially damaged the Solar Irrigation Lifting System in Dochhukha-Dzomlingthang-Ritsa Chiwog under Guma Gewog in Punakha. The facility, installed earlier this year to address water shortages in the area, has stopped functioning. Authorities are yet to assess the full extent of the damage.
The flash flood also deposited large quantities of debris on a section of the Punakha-Gasa Highway near Dzomlingthang, disrupting road connectivity. The damage was reported by the Tshogpa, the local government representative of Dochhukha-Dzomlingthang-Ritsa village.
Shintaphu Lake among Bhutan's potentially dangerous glacial lakes
The outburst occurred at Shintaphu Lake, also known as Shintaphu Tsho, situated below Wakila Mountain in Bhutan's Gasa district. The lake lies in the upper reaches of the Mo Chhu river basin, whose waters flow southwards into the Punatsangchhu river system.
Shintaphu is among Bhutan's 17 potentially dangerous glacial lakes. An official of the National Centre for Hydrology and Meteorology (NCHM) said a water-level monitoring station was installed at Taktsimakhang. However, no alert had been triggered at the station when the initial reports of the outburst emerged.
The exact volume of water released from the lake and the extent of the impact downstream were initially unclear.
A glacial lake outburst flood occurs when water accumulated in a lake formed by melting glaciers is suddenly released following the failure or breach of a natural barrier. Such floods can move rapidly through mountain valleys, carrying huge volumes of water, rocks and debris. They can cause extensive damage to roads, bridges, settlements and agricultural land.
India issues flood warning along Sankosh River
The incident raised concerns in India because the Mo Chhu and Punatsangchhu river systems are connected to the Sankosh River, which enters India and flows through parts of West Bengal and Assam.
The Government of India issued a special advisory warning of a possible sudden rise in water levels along the Sankosh River. The alert identified West Bengal's Alipurduar district and Assam's Dhubri district as areas that could be affected.
Precautionary warnings were also issued in vulnerable parts of North Bengal, including the Darjeeling hills, Jalpaiguri and Cooch Behar districts.
According to the advisory, the floodwater was expected to reach the India-Bhutan border within six to eight hours. District administrations were directed to monitor river levels closely and take necessary precautionary measures.
Teams of the National Disaster Response Force (NDRF) and State Disaster Response Force (SDRF) were mobilised in Tufanganj and Boxirhat in Cooch Behar district, both located close to the Sankosh River and the Assam border.
West Bengal Forest Minister and Kumargram MLA Manoj Kumar Oraon appealed to people living along the Sankosh River in Alipurduar district to move to safer places.
In a video message posted on Facebook, Oraon warned that a sudden surge in water could reach the Kumargram area within the next one to one-and-a-half hours. He urged residents to cooperate with the administration and evacuate as a precaution.
BJP MP from Darjeeling Raju Bista also issued a public safety advisory, asking people living along the Sankosh River and its connected tributaries to remain alert and relocate to safer areas.
In a post on X, Bista said a glacial lake outburst had been reported in Bhutan, with overflowing water moving downstream through the Mofu River towards the Sunkosh River. He appealed to residents of the Darjeeling hills, Terai and Dooars regions to follow official safety instructions.
Thousands shifted to relief shelters
West Bengal authorities later said the immediate flood threat had eased and the situation was under control, although monitoring of the river system continued.
Alipurduar Superintendent of Police Amit Kumar Shaw urged residents not to panic, saying the administration was coordinating closely with Bhutanese authorities.
According to Shaw, approximately 4,000 to 5,000 people had been shifted to shelters, including school buildings being used as temporary relief centres. More than 6,000 additional people had also been moved to safer locations as a precaution.
Police, district administration officials and disaster response agencies were working together to manage the situation. SDRF personnel had been deployed, an NDRF team was being mobilised and Civil Defence personnel were assisting with emergency arrangements.
Shaw said information received from Bhutan indicated that the intensity of the water flow had reduced slightly. However, a red alert remained in force for the Sankosh river system.
The administration had arranged dry food, drinking water, toilets and other essential facilities at relief centres. Residents were also warned that floodwaters could carry dead fish, large pieces of wood and concrete debris, creating additional dangers for people near riverbanks.
The Kumargram block administration said residents had been shifted to 18 flood shelters across the block. Schools, community halls, religious institutions and tea garden facilities were being used to accommodate displaced families.
Residents from parts of neighbouring Assam had also moved to safer locations.
Bhutan assesses damage as concerns over GLOF risks grow
In Bhutan, authorities continued assessing the impact of the flood, particularly in the Gasa region. Reports indicated that infrastructure around Gasa Tshachu, a popular natural hot-spring destination, had been damaged. Sections of the road leading towards Laya had also become impassable.
International media reports said the affected area had been evacuated before the floodwaters arrived, helping prevent casualties. However, darkness and strong water currents initially made it difficult to determine the full extent of the damage.
The incident has renewed attention on the risks posed by glacial lake outburst floods in the Himalayan region, where melting glaciers and unstable natural barriers can threaten mountain communities and downstream settlements.
It has also highlighted the importance of effective early warning systems, continuous monitoring of potentially dangerous glacial lakes and timely evacuation measures.
Bhutan and India have existing arrangements for sharing hydrological information and flood forecasts to help protect communities downstream, particularly in West Bengal and Assam. The latest incident underlines the importance of close coordination between the two countries in managing cross-border flood risks.
(Disclaimer :The content of this article is sourced from a news agency and has not been edited by the Mavericknews30 team.)
