Kolkata, Oct 30: Residents along the Sankosh River in north Bengal have been moved to relief camps after a sudden glacial lake outburst in Bhutan triggered a flood warning, raising concerns over rising water levels in districts bordering the neighbouring country. Authorities have activated disaster response arrangements as water released from Shintaphu Lake flows downstream towards the Sankosh, with officials warning that the floodwater could reach the plains within hours.
The outburst occurred on Thursday evening at Shintaphu Lake in Bhutan’s Gasa district, releasing a large volume of water into the Mo Chhu River. The sudden surge damaged infrastructure near the Gasa Shachu hot spring and raised the river’s water level. The full extent of the damage in Bhutan remains unclear.
The warning initially issued on Thursday night was followed by reports of a sharp rise in water levels across several stretches on Friday afternoon. Although the Sankosh had not shown a significant increase by Friday morning, the changing water conditions prompted renewed concern among communities living along its banks.
West Bengal Minister Nisith Pramanik said water from the lake was moving through the Mo Chhu towards the Sankosh and its tributaries. Authorities alerted residents in vulnerable areas and advised them to relocate to safer places.
Pramanik said officials expected the floodwater to reach the plains within five to six hours of the warning. The State Disaster Management Team has been activated, the National Disaster Response Force (NDRF) notified and disaster management volunteers instructed to remain at the affected locations.
The evacuation has disrupted life in parts of Alipurduar district, particularly Kumargram block. Several residents spent the night on a national highway after leaving their homes. When the Sankosh appeared relatively calm on Friday morning, some began returning, but the increasingly muddy appearance of the river prompted many to turn back to the relief camps.
The potential downstream impact stems from the river system connecting Bhutan with north Bengal. Known as Puna Tsang Chhu in Bhutan, the Sankosh originates in northern Bhutan and flows through Assam and West Bengal before joining the Brahmaputra. The Mo Chhu, one of its two largest tributaries, feeds into the river system, making a substantial rise in its water level a concern for downstream areas.
The outburst has also damaged infrastructure in Bhutan. Preliminary reports indicate partial damage to an irrigation project in Punakha and the washing away of a section of the Punakha-Gasa road, disrupting traffic.
Shintaphu is among 17 glacial lakes in Bhutan identified as dangerous. A similar sudden rise in the lake’s water level on August 26, 2021, caused the Mo Chhu to overflow and change its course, washing away the hot spring.
