Indian authorities put districts in the north of the country on high alert on Sunday after part of a Himalayan glacier broke and caused widespread heavy flooding.
Twitter users shared videos of the huge water deluge through a valley.
One video showed what the user described as “scary visuals coming in from Chamoli district in Uttarakhand.”
Another video showed torrents of water smashing against the rocks on the banks of the river Dhauli Ganga.
Officials told Reuters that people were being evacuated from areas near a river fed by the glacier where they had already seen rising water levels.
Locals told the news agency that they feared workers from the nearby hydropower project had been swept away by the flood as well as other villagers who had been near the river at the time.
“We have no idea how many people are missing, ” villager Sanjay Singh Rana said.
The videos shared on social media showed how the dam was unable to hold back the sheer weight of water.
100-150 feared dead
The chief secretary for the Uttarakhand state, Om Prakesh, told Reuters that 100 to 150 people were feared dead, but “the actual number has not been confirmed yet.”
The Indian Express said that part of the Nanda Devi glacier broke off on Sunday morning, two days after an avalanche on the same glacier.
Prime Minister Narendra Modi tweeted that he was “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,” he added.
The Uttarakhand province in the mountainous Himalayas region is prone to heavy flooding. In June 2013, record-breaking rainfall led to devastating floods that left almost 6,000 people dead.