Bhutan glacial lake outburst triggers flash flood, high alert in north Bengal; villages evacuated

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 Bengal-Assam border

A glacial lake outburst in Bhutan has triggered a flash flood, washing away infrastructure at a major tourist site and prompting a high flood alert in parts of northern Bengal and Assam. Authorities have begun evacuating vulnerable riverbank settlements along the Sankosh river and its tributaries amid fears of a sudden rise in water levels. No casualties have been reported in Bhutan.

Flash flood washes away infrastructure at Bhutan tourist site

The flood, triggered by the Shintaphu glacial lake bursting its banks, washed away infrastructure at the Gasa Tshachu natural hot springs in northern Bhutan, media reports said on Friday.

The extent of the damage from the late-night flash flood was not immediately known due to "darkness and the strong flow" of floodwaters, Bhutan's state broadcaster BBS reported. Two Bailey bridges, built using portable, pre-fabricated sections, may also have been washed away.

Bhutan's national newspaper Kuensel reported that part of the road leading to Laya village, where the hot springs are located, had been washed away, rendering it impassable. The road has been closed to traffic indefinitely.

The area had been evacuated before the floodwaters reached it, Kuensel reported. No injuries or loss of life have been reported, according to BBS.

Gasa Tshachu, a major tourist attraction in northern Bhutan, was also hit by a flash flood in 2021, when the Mochhu River changed course and swept through the area.

North Bengal villages evacuated as Sankosh water levels threaten to rise

The glacial lake outburst flood (GLOF) has triggered a high flood alert in parts of northern West Bengal, with residents of riverbank villages in Alipurduar district leaving their homes with cattle following evacuation instructions.

Nearly 7.4 million cubic metres of water surged out of the breached Shintaphu Lake into the Mo (Mofu) river, raising concerns over a sudden rise in the water level of the Sankosh, which flows along the West Bengal-Assam border.

Evacuation measures began late Thursday night in villages along the Sankosh. Loudspeaker announcements were made in riverbank settlements under the Rampur-I gram panchayat area, asking residents to move to designated shelters.

Officials warned that the surge could reach border areas within six to eight hours, potentially inundating vulnerable settlements in West Bengal and Assam.

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 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," Pramanik said in a video message.

He also urged residents living near riverbeds in Tufanganj and adjoining areas of Cooch Behar to evacuate immediately.

Pramanik said the administration was prepared to deal with any eventuality, with State Disaster Response Force (SDRF) and National Disaster Response Force (NDRF) teams 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.

Centre issues flood advisory for Bengal and Assam

A special advisory issued by the Union Ministry of Jal Shakti on Thursday 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 Bengal's Alipurduar districts, the advisory said.

Local authorities in both districts have been asked to remain alert, closely monitor the situation and take necessary precautionary measures.

The India Meteorological Department (IMD) has also forecast heavy rainfall in Alipurduar on Friday, 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 threaten hydropower infrastructure.

Bhutan hot springs had faced flash flood in 2021

Gasa Tshachu, located in the Himalayan kingdom nestled between India and China, is a major tourist attraction in northern Bhutan. The area had experienced another flash flood in 2021 after the Mochhu River changed course and swept through the region.

In neighbouring Nepal, a flash flood in a similar mountainous area along the border with China in August killed more than 1,500 people and left more than 5,000 missing.