Glacial lake outburst in Bhutan triggers flood alert in West Bengal and Assam

New Delhi:- The Central Water Commission (CWC) has issued a special flood advisory for West Bengal and Assam following a reported Glacial Lake Outburst Flood (GLOF) at Shintaphu Lake in Bhutan. The Commission has warned of a sudden rise in water levels in the downstream areas of Alipurduar district in West Bengal and Dhubri district in Assam.

In its advisory issued on October 29, the CWC said the incident was reported by the Indian Embassy in Bhutan. The outburst could trigger flash floods in the upper reaches of the Punatsangchhu River, which is known as the Sankosh River in India.

According to the advisory, floodwaters were expected to reach the India-Bhutan border within six to eight hours, posing a potential threat to low-lying areas along the river system.

The Commission has advised local authorities in both districts to remain on high alert, closely monitor river levels and take necessary precautionary measures to protect people living in vulnerable areas.

Meanwhile, Assam Chief Minister Himanta Biswa Sarma is closely monitoring the situation. The Chief Minister’s Office said the Dhubri district administration was prepared to deal with any possible downstream impact.

In West Bengal, disaster response teams have been placed on alert in vulnerable areas along the Sankosh River. Authorities have also advised residents of low-lying settlements to move to safer locations as a precaution. No confirmed major downstream damage in India had been reported in the latest information available.

In Bhutan, the reported glacial lake outburst occurred on Thursday evening at Sintaphu Lake near Wakila Mountain in the Lungo area of Gasa district.

According to Bhutanese media reports, floodwaters reached Taktsemakhang at around 8:15 PM, damaging a road connecting the remote highland community of Laya. The flood also washed away infrastructure at the Gasa Tshachu hot springs and damaged sections of the Punakha-Gasa highway, disrupting road connectivity.

Bhutan’s state broadcaster, Bhutan Broadcasting Service, reported that no deaths or injuries had been reported, as people in vulnerable areas were evacuated before the floodwaters arrived. Two temporary Bailey bridges were also feared to have been swept away. Authorities are assessing the damage, while the historic Punakha Dzong has been closed until further notice as a precautionary measure.

Bhutan’s National Centre for Hydrology and Meteorology is monitoring water levels along the Mo Chhu River at Tashithang and Yebisa. Warning sirens have been activated along downstream stretches of the Mo Chhu and Punatsangchhu rivers.

The Punatsangchhu-II Hydropower Project has also reportedly stopped power generation and opened its dam gates as a precaution against floodwaters and debris.

Sintaphu Lake is among Bhutan’s 17 potentially dangerous glacial lakes. It lies near the headwaters of the Mo Chhu River, which joins the Pho Chhu at Punakha to form the Punatsangchhu River before flowing into India as the Sankosh. Bhutanese authorities are continuing to assess the lake’s condition, the volume of water released and the downstream impact.