Rescue teams are working non-stop to rescue 37 power plant workers that were trapped in a tunnel after part of the Himalayan glacier fell into a river, causing a devastating avalanche that left at least 26 people dead and 165 missing.

More than 2,000 members of the military and police worked through the night to find survivors trapped in the northern state of Uttarakhand after Sunday’s flood.

Indo Tibetan Border Police spokesperson Vivek Pandey said that a hydroelectric plant on the Alaknanda was destroyed, and a plant under construction on the Dhauliganga was damaged.

12 workers who were trapped at a tunnel at the Dhauliganga plant were rescued on Sunday.

According to officials, the focus of the search-and-rescue operations was saving the 37 other workers stuck in another tunnel.

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

Rescuers fear that many more died during the horrific avalanche, and had been searching downstream for bodies by boat and by walking along riverbanks.

Rescuer Rakesh Bhatt said they were working in the tunnel when water rushed 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.

The flood occurred after a portion of the Nanda Devi glacier broke off Sunday morning, unleashing the water trapped behind it.

The Himalayan region had been vulnerable to flash floods and landslides, as well as to  rising global temperature caused by man-made climate change.

A study conducted in 2019 found that the Himalayan glaciers had been melting twice as fast during the last century, and had lost almost half a meter of ice each year.