At least 18 people are dead and as many as 200 are missing after a piece of a Himalayan glacier broke off Sunday (Feb. 7), triggering an avalanche and flash flood that smashed through a nearby hydroelectric dam. A second dam, located further downstream, was also damaged by the flood, according to the BBC.
Video recorded by bystanders shows the raging floodwaters surging through a rocky valley in Uttarakhand – an Indian state in the Himalayas bordering China and Nepal – before ripping through the dam with a battering ram of rocks, mud, ice and debris.
Many of the missing are believed to be employees who were working at the two dams, according to news reports. More than a dozen workers were rescued from a flooded tunnel on Sunday, but as many as 40 others may still be trapped in a second tunnel, the BBC reported.
Glorious footage of a labourer being rescued from the sediment inundated area near Tapovan tunnel area by ITBP personnel. Watch full. @IndiaToday #Uttarakhand pic.twitter.com/eGe1oYEISuFebruary 7, 2021
The avalanche began around 10:45 a.m. local time (12:15 a.m. EST) Sunday, when part of the Nanda Devi glacier broke off of a high peak and plummeted into the river below. The glacier sits atop a mountain of the same name; soaring more than 25,600 feet (7,800 meters) high, Nanda Devi is the second-tallest mountain in India. (At a dizzying 28,160 feet, or 8,580 m, Kangchenjunga, which sits on the border with Nepal, is the tallest mountain in India and the third tallest in the world.)
Indian authorities are still investigating the cause of the avalanche. However, the Himalayan glaciers of Uttarakhand are known to be extremely fragile, and climate change has significantly accelerated their melt rate. A 2019 study in the journal Science Advances calculated that the average rate of ice loss in the Himalayas doubled between 1975 and 2016, while the Hindu Kush Himalaya Assessment report predicted that one-third of the region's glaciers could be gone by the end of the century, even if the world's most ambitious climate targets are met.
Environmentalists have long cautioned against major infrastructure projects in the fragile region, according to NPR. Uttarakhand experienced an even greater tragedy in 2013, when record monsoon rainfall triggered floods that killed roughly 6,000 people. The catastrophe, which has been called the "Himalayan tsunami," wiped countless villages, bridges and roads off the map.
Originally published on Live Science.