Alipurduar on alert as Bhutan's Shintaphu glacial lake bursts, raising Sankosh river levels

Late on Thursday, a message from Bengal's forest minister, Manoj Oraon, went out to people living along the Sankosh river in Alipurduar district: stay alert, the water may rise, and flash floods are possible.

The warning followed reports that Shintaphu Lake, a glacial lake in Bhutan's Gasa district, had burst its banks that evening. According to local reports, the lake sits below Wakila Mountain in Lungo, in Laya Gewog. It lies in the upper reaches of the Mo Chhu river basin, and the Mo Chhu catchment feeds into the Sankosh river system downstream. That connection is why a lake high in the Bhutanese mountains became a concern for villages across the border in West Bengal.

Oraon named the places he wanted watched. His message urged residents of Kumargram tea estate, Kumargram forest village, Pakriguri and Bholka, all in Alipurduar's Kumargram area, to keep an eye on rising levels in the Sankosh. He cautioned that flash floods were possible in nearby areas.

On the Bhutanese side, the reports said people in the affected area had already been moved to safer ground. The source does not say how many people were relocated or which settlements were involved. Locals were expected to begin assessing livestock losses on Friday, which suggests animals were affected, though no figures have been given.

Shintaphu Lake is considered one of 17 potentially dangerous glacial lakes. That label marks it as a lake already watched for the chance of a sudden release of water, and Thursday's outburst, if the local reports hold, is the event that classification anticipates.

Much is still unsettled. The reporting rests on local accounts of the outburst, and the source gives no measurement of how much water was released, no reading of how high the Sankosh has risen, and no report of damage on the Indian side. The alert in Kumargram is a precaution tied to the possibility of flooding, not a report that flooding has occurred.

What comes next is practical. On Friday, people in Gasa are expected to count livestock losses, and the water levels in the Sankosh downstream will show whether the alert in Kumargram, Pakriguri and Bholka was a margin of safety or the start of something worse.