Glacial Lake Outburst Flood damages roads, washes away bridge in Bhutan

GELEPHU (BHUTAN) A glacial lake outburst flood (GLOF) in Shintapu Tsho in the Laya area of northwestern Bhutan’s Gasa district on Thursday night (October 29, 2026) triggered flooding along the Mochhu, damaging roads, bridges and public infrastructure in two districts.

Officials on Friday (October 30, 2026) said no human casualties have been reported, but there are growing concerns over a large artificial lake formed near Taktsemakhang, about 2,000 feet downstream of Laya. The accumulation of water at the confluence of the flood-affected channels of Mochhu (river) has raised fears of another sudden outburst, which could be disastrous for downstream areas.

Officials said they could not immediately assess the GLOF impact on Thursday night (October 29, 2026). Royal Bhutan Army personnel stationed at Taktsemakhang and people near Gasa Tshachu, a hot spring, were instructed to evacuate to a safer location.

“Prime Minister Tshering Tobgay is in Laya to assess the artificial lake at Taktesakhang, while Industry, Commerce and Employment Minister Namgyel Dorji is monitoring the situation in Punakha,” a Department of Local Governance and Disaster Management official said.

Punakha and Thimphu districts are south of Gasa, which borders the Tibetan Autonomous Region. These and other neighbouring districts were put on high alert for potential danger from the GLOF-induced artificial lake.

According to disaster management officials, Gasa Tsachu, one of Bhutan’s popular hot spring destinations, suffered extensive damage due to Thursday’s (October 29, 2026) GLOF. Floodwaters washed away almost all public facilities in the area.

This was the second flood-related damage at Gasa Tshachu since August 26, 2021, when the swollen Mochhu changed course towards the area.

The GLOF also damaged two vital roads in Gasa district and swept away a Bailey bridge in Punakha district. The bridge was constructed in 2022 with support from the Government of India.

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In Assam, Chief Minister Himanta Biswa Sarma said the State government was closely monitoring the possible impact of the Bhutan GLOF. “The vulnerable revenue circles in (western Assam’s) Dhubri and Kokrajhar districts have been put on high alert,” he said.

Shintaphu Tsho (Lake), located at the source of the Mochhu, is among Bhutan’s 17 glacial lakes identified as potentially dangerous. The Mochhu, considered female, and Phochhu (male) meet in Punakha district to form the Punatsangchhu, which flows along the Assam-West Bengal border as the Sonkosh River.