This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel search for more than three dozen power plant workers trapped ...
This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel search for more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (National Disaster Response Force via AP)
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trap...
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (AP Photo/Rishabh R. Jain)
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trap...
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (AP Photo/Rishabh R. Jain)
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trap...
Indo Tibetan Border Police (ITBP) personnel using heavy machinery to clear debris as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (AP Photo/Rishabh R. Jain)
This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel carry a dead body recovered from debris after a portion of th...
This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel carry a dead body recovered from debris after a portion of the Nanda Devi glacier snapped off Sunday morning, releasing water trapped behind it in Reni, northern state of Uttarakhand, India, Tuesday, Feb.9, 2021. (National Disaster Response Force via AP)
Activists of Socialist Unity Center of India (SUCI) light candles in Ahmedabad, India, for the victims of glacier flooding in the northern state of Ut...
Activists of Socialist Unity Center of India (SUCI) light candles in Ahmedabad, India, for the victims of glacier flooding in the northern state of Uttarakhand, Monday, Feb. 8, 2021. Rescuers were working Monday to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain. (AP Photo/Ajit Solanki)
Activists of Socialist Unity Center of India (SUCI) light candles in Ahmedabad, India, for the victims of glacier flooding in the northern state of Ut...
Activists of Socialist Unity Center of India (SUCI) light candles in Ahmedabad, India, for the victims of glacier flooding in the northern state of Uttarakhand, Monday, Feb. 8, 2021. Rescuers were working Monday to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain. (AP Photo/Ajit Solanki)
This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel search for more than three dozen power plant workers trapped ...
This photograph provided by National Disaster Response Force (NDRF) shows NDRF personnel search for more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (National Disaster Response Force via AP)
This photo provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear debris as they try to rescue more than three do...
This photo provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear debris as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (Indo Tibetan Border Police via AP)
A hydro project vehicle is seen stuck in slash and mud at Reni village in the Tapovan area of Chamoli district, in Indian state of Uttrakhund, Monda...
A hydro project vehicle is seen stuck in slash and mud at Reni village in the Tapovan area of Chamoli district, in Indian state of Uttrakhund, Monday, Feb.8, 2021. Rescuers were working Monday to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain. (AP Photo)
Rescuers leave on a boat to search for bodies in the downstream of Alaknanda River in Rudraprayag, northern state of Uttarakhand, India, Monday, Feb.8...
Rescuers leave on a boat to search for bodies in the downstream of Alaknanda River in Rudraprayag, northern state of Uttarakhand, India, Monday, Feb.8, 2021. More than 2,000 members of the military, paramilitary groups and police have been taking part in search-and-rescue operations after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain. (AP Photo/Rishabh R. Jain)
This grab from video provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear muck as they try to rescue more than ...
This grab from video provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear muck as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (Indo Tibetan Border Police via AP)
This photo provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear muck as they try to rescue more than three doze...
This photo provided by Indo Tibetan Border Police (ITBP) shows ITBP personnel using machinery to clear muck as they try to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain in Tapovan area of the northern state of Uttarakhand, India, Monday, Feb.8, 2021. (Indo Tibetan Border Police via AP)
Rescuers leave on a boat to search for bodies in the downstream of Alaknanda River in Rudraprayag, northern state of Uttarakhand, India, Monday, Feb.8...
Rescuers leave on a boat to search for bodies in the downstream of Alaknanda River in Rudraprayag, northern state of Uttarakhand, India, Monday, Feb.8, 2021. More than 2,000 members of the military, paramilitary groups and police have been taking part in search-and-rescue operations after part of a Himalayan glacier broke off Sunday and sent a wall of water and debris rushing down the mountain. (AP Photo/Rishabh R. Jain)
JOSHIMATH, India (AP) — Hundreds of rescue workers were scouring muck-filled ravines and valleys in northern India on Tuesday looking for survivors after part of a Himalayan glacier broke off, sending a devastating flood downriver that has left at least 26 people dead and 165 missing.
One of the rescue efforts is focused on a tunnel at a hydroelectric power plant where more than three dozen workers have been out of contact since the flood occurred Sunday. Rescuers used machine excavators and shovels to clear sludge from the tunnel overnight in an attempt to reach the workers as hopes for their survival fade.
The disaster was set off when part of a glacier on Nanda Devi mountain snapped off Sunday morning. Scientists have gone to the site to investigate what caused the break and the flood — possibly an avalanche or a release of accumulated water. Experts say climate change may be to blame since warming temperatures are shrinking glaciers and making them unstable worldwide.
The floodwater, mud and boulders roared down the mountain along the Alaknanda and Dhauliganga rivers, breaking dams, sweeping away bridges and forcing the evacuation of many villages while turning the countryside into what looked like an ash-colored moonscape.
The flood swept away a small hydroelectric project and damaged a bigger one downstream on the Dhauliganga. Flowing out of the Himalayan mountains, the two rivers meet before merging with the Ganges River.
The power of the roaring wall of water was first noticed by residents of multiple villages perched on the valley slopes.
Rajeev Semwal heard a sound similar to rumbling clouds and then watched the usually blue waters of Alaknanda turn muddy. “I understood disaster had indeed struck,” said Semwal, a resident of Tapovan village in Uttarakhand state where the power plant is located.
Semwal’s brother-in-law and younger brother both worked at the power plant. His younger brother was inside the tunnel that was flooded and has not been heard from since.
Most of the missing were people working on the two projects, part of many plants the government has been building on several rivers and their tributaries in the mountains of Uttarakhand state.
The ecologically sensitive Himalayan region is prone to flash floods and landslides.
More than 6,000 people are believed to have been killed in floods in 2013 which were triggered by the heaviest monsoon rains in decades.
