At least seven dead as glacial lake bursts in Sikkim

Flash floods, believed to have been triggered after a lake, forming from the gradual melting of a Himalayan glacier, suddenly overflowed and inundated the Teesta river basin, destroyed Chungthang dam, a key component of the Sikkim’s largest hydroelectric project, and washed away highways, villages, and towns.

At least seven people have died and scores more were injured or missing after flash floods inundated Sikkim on October 4. The floods are believed to have been triggered after a lake, forming from the gradual melting of a Himalayan glacier, suddenly overflowed and inundated the Teesta river basin.

Sikkim flash floods | Updates

This destroyed the Chungthang dam, a key component of the State’s largest hydroelectric project, and washed away highways, villages, and towns. The worst affected districts were Mangan, Gangtok, Pakyong, and Namchi. Twenty-two Army personnel were among those reported missing.

The South Lhonak lake in northern Sikkim is situated about 5,200 metres above sea level. Scientists have previously warned that the lake had been expanding over years, possibly from the melting of the ice at its head. Nearly half the lake was drained out, according to a press statement by the National Disaster Management Agency (NDMA). This was likely caused by an “avalanche from the ice-capped feature.”

The Chungthang dam, a concrete-rock dam, was breached from its centre from the sheer force and speed of the water, estimated at nearly 54 kmph.

“There is significant damage. However as of [Wednesday evening], the water from the lake has receded. It was a 160-hectare glacial lake and now it is about 60 hectares. So all that water has flowed down. Rains are expected for the next two days. Currently, the dam and its surroundings are inaccessible and it will be a few days before we get greater clarity,” a top official in government, who declined to be identified, told The Hindu.

“The distance between the lake and the Teesta 3 [power project] is very short. The CWC [Central Water Commission] reported a rising column of water at 1:30 a.m., but it was so quick and big that little could be done by way of warning,” the official added.