Indian rescue crews spent hours Monday trying to rescue victims who were trapped after a Himalayan glacier broke off and sent water and debris flying into two hydroelectric plants, leaving at least 31 dead and 165 missing, the Associated Press (AP) reported.

A government official told the AP they’re unsure of the number of people who were working in the Dhauliganga project when the floodwaters hit.

“The number of missing people can go up or come down,” the official said.

Video captured by witnesses show a flood of water and debris crashing through a dam that is part of the Rishiganga Hydroelectric Project. The dam crumbles into pieces before continuing to rush downstream.

“It came very fast, there was not time to alert anyone,” Sanjay Singh Rana, who lives near the river Raini village, told Reuters. “I felt that even we would be swept away.”

The flood was triggered when a piece of the Nanda Devi glacier snapped off in the morning, sending all the water trapped behind it rushing down the mountain and into other bodies of nearby water, according to the AP. Villages along the bank of the Alaknanda and Dhauliganga rivers were evacuated, according to the AP.

A hydroelectric plant along the Alaknanda was destroyed and a plant that was under construction on the Dhauliganga was severely damaged, according to the AP.

Rescuers have focused their efforts on saving 37 workers who are trapped inside a tunnel at one of the hydroelectric plants, according to the AP. (RELATED: Man Holds Onto Tree For 16 Hours During Floods That Have Killed At Least 1,000)

“The tunnel is filled with debris, which has come from the river. We are using machines to clear the way,” H. Gurung, a senior official of the paramilitary Indo Tibetan Border Police, according to the AP.

Video posted by the Indo-Tibetan Border Police (ITBP) Facebook page shows rescuers saving a man who was trapped inside one of the tunnels. Twelve people were rescued from the tunnel and three were found unconscious, according to the ITBP.

The three unconscious individuals were later treated and are in stable condition, according to the ITBP.

 

Chief Minister Trivendra Singh Rawat, Uttarakhand’s top elected official, said rescuers had to use ropes and shovels to reach the tunnels, according to the AP.

“The rescuers used ropes and shovels to reach the mouth of the tunnel. They dug through the debris and entered the tunnel. They are yet to come in touch with the stranded people,” Rawat said.

One of the workers rescued from the tunnel, Rakesh Bhatt, told the AP they were working when all of a sudden water began rushing in.

“We thought it might be rain and that the water will recede. But when we saw mud and debris enter with great speed, we realized something big had happened,” he said.

Bhatt said one of his coworkers was able to call officials, according to the AP.

“We waited for almost six hours – praying to God and joking with each other to keep our spirits high. I was the first to be rescued and it was a great relief.”

Indian Prime Minister Narendra Modi said he was monitoring the “unfortunate situation.”

Am constantly monitoring the unfortunate situation in Uttarakhand. India stands with Uttarakhand and the nation prays for everyone’s safety there. Have been continuously speaking to senior authorities and getting updates on NDRF deployment, rescue work and relief operations.

— Narendra Modi (@narendramodi) February 7, 2021

This story is developing and will be updated as more information becomes available.