Glacial lake outburst flood hits Bhutan, damages roads and bridge, raises alarm in Assam

A glacial lake outburst flood (GLOF) from Shintapu Tsho in the Laya area of Bhutan's Gasa district on the night of October 29, 2026 caused flooding along the Mochhu river, damaging roads, bridges and public facilities in the district. No human casualties were reported, but authorities expressed concern over a newly formed artificial lake near Taktsemakhang, about 2,000 feet downstream, which could trigger another sudden outburst.

Royal Bhutan Army personnel and residents near the Gasa Tshachu hot spring were ordered to evacuate. Prime Minister Tshering Tobgay travelled to Laya to assess the artificial lake, while Industry, Commerce and Employment Minister Namgyel Dorji monitored the situation in Punakha, a Department of Local Governance and Disaster Management official said.

The flood washed away most public facilities at Gasa Tshachu, a popular hot-spring destination, and swept away a Bailey bridge in Punakha district that had been built in 2022 with assistance from the Government of India. Two key roads in Gasa district were also damaged.

Neighbouring districts, including Punakha and Thimphu, were placed on high alert for potential hazards from the artificial lake. In India's Assam state, Chief Minister Himanta Biswa Sarma said the government was closely monitoring possible impacts, noting that the revenue circles in Dhubri and Kokrajhar districts have been put on high alert.

Shintapu Tsho is one of Bhutan's 17 glacial lakes identified as potentially dangerous. The Mochhu river joins the Phochhu river in Punakha district to form the Punatsangchhu, which continues as the Sonkosh River along the Assam-West Bengal border.