Uttarakhand Chief Minister Trivendra Singh Rawat on Sunday announced Rs 4 lakh compensation for those killed by floods in the state and said it was for experts to find out the cause while the government was focused on saving lives.
Around 125 people were missing after a Himalayan glacier broke and swept away a hydroelectric dam down the Rishiganga valley on Sunday, with floods forcing the evacuation of villages downstream.
Uttarakhand is prone to flash floods and landslides and the disaster prompted calls by environment groups for a review of power projects in the ecologically sensitive mountains.
Earlier state chief secretary Om Prakash said 100 to 150 people were feared dead. A large number of the missing were workers at the 13.2 MW Rishiganga Hydroelectric Project which was destroyed by the bursting of the glacier.
Footage shared by locals showed the water washing away parts of the Rishiganga dam and everything else in its path. At least 180 sheep were washed away.
Twelve people who had been trapped in a tunnel had been rescued and efforts were under way to save others caught in another tunnel, the federal home ministry said after a meeting of the National Crisis Committee, comprising top officials.
"India stands with Uttarakhand and the nation prays for everyone's safety there," Prime Minister Narendra Modi said on Twitter.
State utility NTPC said the avalanche had damaged a part of its Tapovan Vishnugad hydropower plant that was under construction further down the river. It gave no details but said the situation is being monitored continuously.
It was not immediately clear what had set off the avalanche at a time when it is not the flood season. In June 2013, record monsoon rains in Uttarakhand caused devastating floods that claimed close to 6,000 lives.
That disaster was dubbed the "Himalayan tsunami" because of the torrents of water unleashed in the mountainous area, which sent mud and rocks crashing down, burying homes, sweeping away buildings, roads and bridges.