Several labourers, who were working at the Rishi Ganga hydroelectric power project, are feared missing after a glacier broke in Dhauli Ganga valley in Joshimath on Sunday morning, said the sources.
A dam of the Tapovan power project was breached and feared to have been washed away.
Personnel of ITBP and SDRF have been rushed to the affected areas to evacuate stranded people.
The rivers in the region have witnessed flash floods after the glacier broke.
Trivendra Singh Rawat, the Uttarakhand Chief Minister, has convened an emergency meeting to take stock of the situation and to supervise rescue and relief operations.
Rishikesh and Haridwar towns have been put on an alert as a precautionary measure even though the impact of the disaster may not be felt there.
There was not much human habitation at the site where the glacier broke but a number of power projects have been hit, informed a government spokesman.
The government has also appealed to the area people not to venture near the Ganga river.
Following the mishap, Uttar Pradesh authorities have put the state on high alert, official sources said on Sunday.
All the District Magistrates of UP districts situated along the Ganga river have been directed by Chief Minister Yogi Adityanath to be on high alert and monitor water levels continuously, a government spokesman said.
“If required, people will be evacuated to safe places. National Disaster Response Force, SDRF and Uttar Pradesh Provincial Armed Constabulary have also been put on highest alert,” the spokesman said.
(With IANS inputs)