(BBC) – Emergency workers are searching for as many as 200 people still missing after a piece of a Himalayan glacier fell into a river and triggered a huge flood in northern India, killing 18.
The floodwaters burst open a dam and a deluge of water poured through a valley in the state of Uttarakhand on Sunday.
Most of the missing are believed to be workers from two hydropower plants.
The rescue effort is focused on several sites, including a tunnel more than 200 metres (656ft) long.
More than 30 people were apparently trapped inside when the torrent of icy water swept down the valley, carrying rocks and earth as it gathered speed.
There has been no contact with them since. The rescue teams hope to clear the tunnel by nightfall.
Hundreds of troops, paramilitaries and military helicopters have been sent to the region to help with rescue efforts.
An investigation is continuing into what caused the glacial burst.
Speaking from hospital, one man described the moment the tunnel flooded.
“We heard screams, ‘get out, get out’. We didn’t know what was happening. We started running to escape when the force of the water gushed in through the mouth of the tunnel. We couldn’t get out because of that,” he said.
“We held on to the [roof] of the tunnel. We held on for about an hour. As the water receded, we slowly climbed onto the big rocks that flowed in, to take a breath. We had lost hope. We didn’t think we would survive.”
Uttarakhand police said an avalanche struck at about 11:00 local time (05:30 GMT) on Sunday, destroying a dam known as the Rishiganga Hydroelectric Project.
Police said the impact catapulted water along the Dhauliganga river, damaging another power project downstream in the Tapovan area.
Senior police officials said a bridge in the Tapovan area that connected 13 villages was washed away in the avalanche. Food packets were air dropped in some of these villages.