NEW DELHI – A Himalayan glacier broke, causing sudden, massive flooding in the northern Indian state of Uttarakhand on Sunday, destroying two dam projects and forcing authorities to try to evacuate villages and save more than 100 lives.

Trivendra Singh Rawat, the prime minister of Uttarakhand, said seven bodies had been recovered and that about 125 people, including many workers on the two largely swept away hydropower projects, were not reported.

“An avalanche came and completely broke the Rishiganga power plant project and almost all of the workers there are missing,” said Ashok Kumar, the Uttarakhand police chief. “When the water came downriver, we alerted the people.”

The scenes were reminiscent of floods in Uttarakhand in 2013, when heavy rain for several days led to landslides in which thousands of people were killed and entire villages were washed away.

But the latest disaster has also aroused fears about what is to come. Scientists who said a glacier breaking in the middle of winter was a result of climate change have warned that rising temperatures are melting Himalayan glaciers at an alarming rate. The glaciers that provide water to tens of millions of people may have largely disappeared by the end of the century, according to a recent study.

The Chamoli district in Uttarakhand appeared to be hardest hit by the flowing Dhauliganga River. Amit Shah, India’s interior minister, said the country’s disaster relief teams had been flown in. Hundreds of soldiers and members of the Indian-Tibetan border police were also there, other officials said.

Videos on social media showed violent water fluctuations down the mountain canyons, washing away bridges, and what hydroelectric power stations looked like one of the dams.

Officials said 35 people were working on the Rishiganga power plant project, which was closer to the swept glacier, and 176 others were working on a second project about three miles downstream.

Ratan Singh Rana, 55, from Raini village near the Rishiganga Project, said the water flowed down the mountain around 10:30 a.m.

“I was sitting on the floor of my house,” he said. “I saw black liquid flowing from the Nanda Devi mountainside – with a lot of noise downwards – as if a volcano had erupted.”

“It was only 20-25 meters from us,” he added. “We ran uphill about 250 meters and kept crying and shouting, ‘Bhago, bhago! Bachao, bachao! “He said, using the Hindi words for” run “and” save us! ” “

Mr. Rana said the muddy water swept large boulders and ice downstream. His daughter and granddaughter were trapped in the house, and mud debris locked the main entrance. You managed to save her from the back of the house.

“We thought the whole world would drown in it,” he said. “I thought that today is the end, that we would leave this world today.”

Late on Sunday afternoon, the worst damage from the flooding appeared to be over.

Prime Minister Mr Rawat visited Chamoli and posted a video on Twitter indicating that water flow had slowed. He expressed hope that some of the missing could be saved. Local media reports say 16 people trapped in a tunnel have so far been rescued.

“Our particular focus is on rescuing the workers trapped in the tunnels,” he said.

The disaster led critics to point fingers at the government for building a dam near the glaciers at a time when the area is so vulnerable to climate change.

Uma Bharti, a former minister of water resources and river development in Prime Minister Narendra Modi’s government, said she had warned against placing a hydropower project on the river near the Himalayas.

“This incident, which occurred near Rishiganga in the Himalayas, is both worrying and cautionary,” Ms. Bharti said on Twitter. She said she warned that the Himalayas “is a very sensitive area and therefore these projects on the Ganges and its tributaries should not be built.”

Anil Joshi, an environmentalist who studies the Himalayan region, said the swept-away dam was built on India’s second highest mountain just a few kilometers from the Nanda Devi Glacier.

“At this point, a glacier avalanche is indicative of climate change,” Joshi said, referring to how the episode happened during the winter cold. “Changes in temperature caused glaciers to detach and damaged the dam in Rishiganga.”

Mr Joshi said he had difficulty understanding why the government built the dam so close to the glacier. “Now this water is flowing at cyclone speed.” he said.