Shintaphu Lake in Gasa district ruptured Thursday night, unleashing a torrent that obliterated the Gasa Tshachu hot‑spring complex.
Officials had already moved residents out of the hot‑spring zone, sparing any fatalities.
Shintaphu, one of 17 high‑risk glacial lakes in Bhutan, has previously triggered a major flood in August 2021 that diverted the Mo Chhu river.
Floodwaters crossed Srigang in Kabesa Gewog, reaching a point eight kilometres from Punakha Dzong, and surged downstream toward the Sankosh River.
The government has issued flash‑flood alerts to West Bengal’s Alipurduar, Jalpaiguri, Darjeeling hills and Assam’s Dhubri, urging residents to stay calm.
Amit Kumar Shaw, Superintendent of Police, Alipurduar, told reporters: "We’re in alert mode, the administration is fully prompt, and all agencies are actively working— we expect to resolve the situation within two to three hours."
The flood also damaged the Solar Irrigation Lifting System in Punakha‑Guma, halting irrigation for several villages.
Both Bhutan and Indian authorities are monitoring water levels closely; a joint hydrological assessment is slated for tomorrow morning.