The death toll from a glacial lake burst in northeastern India earlier this week has climbed to at least 40 while dozens of others remain missing, government officials said Friday.
The Lhonak Lake in the mountainous Sikkim state burst through a major hydroelectric dam Wednesday, causing major flooding that authorities said had impacted the lives of 22,000 people.
The flood began shortly after midnight Wednesday, when a glacial lake high in the mountains overflowed after a heavy rainfall. The waters cracked open a 6-year-old dam that was the largest in the Indian state of Sikkim, and then cascaded through towns in the Lachan Valley below.
It was the latest deadly flood to hit northeast India in a year of unusually heavy monsoon rains. Nearly 50 people died in flash floods and landslides in August in nearby Himachal Pradesh state, record rains in July killed more than 100 people over two weeks in northern India.
A report compiled by the Sikkim State Disaster Management Authority in 2019 had identified Lhonak Lake as "highly vulnerable" to flooding that could cause extensive damage to life and property in downstream areas, warning of the risk of flash floods that could break through dams.
The design and placement of the Teesta-3 dam were controversial from the time it was built, part of an Indian government push to expand hydropower energy. Local activists argued that extreme weather caused by climate changes makes dam-building in the Himalayas too dangerous.
A 2021 study by researchers in India, the United States and Switzerland warned that the dam posed a growing risk of catastrophic floods as a warming climate causes the glaciers that feed it to melt faster.
"Despite being the biggest project in the state, there were no early warning systems installed even though the glacier overflowing was a known risk," said Himanshu Thakkar of the non-governmental organization South Asian Network for Rivers, Dams and People.
According to a release from India’s National Disaster Management Agency Friday, they plan to set up early warning systems for real-time alerts at most of India's 56 known at-risk glacial lakes.
Thakkar said authorities failed to apply the lessons from a 2021 dam breach in Himalayan state of Uttarakhand that killed 81 people, allowing an "eerily similar" disaster to occur.
The dam’s operator, and local agencies responsible for dam safety, did not respond to requests for comment Friday.
In 2021, the Indian federal government passed a dam safety law that requires operators and local governments to plan for emergencies, but the Teesta-3 dam is not listed as being monitored for safety by India’s chief dam regulator, the Central Water Commission.
It wasn’t clear what triggered the breach Wednesday.
Experts and varying government reports have pointed to sudden, intense rains in the area, and a 6.2 magnitude earthquake that struck nearby Nepal on Tuesday afternoon.
"We knew that this was coming," said Gyatso Lepcha, general secretary of Affected Citizens of Teesta, an environmental organization based in Sikkim. "The same can happen with other dams also," he wrote, in a statement that called for a safety review of all dams in the state.
More than 2,000 people were rescued after Wednesday’s floods, the Sikkim State Disaster Management Authority said in a statement, adding that state authorities set up 26 relief camps for more than 22,000 people impacted by the floods.
