There was a massive flood in Uttarakhand's Joshimath area due to the water level in Dhauliganga river suddenly crossing its regular flow on Sunday morning followed by an avalanche near a power project at the Reni village of Chamoli district.

The incident took place near the Reni village, which is 26 km far from Joshimath. The Dhauliganga river got flooded and destroyed many houses situated at the river banksides. 100-150 casualties feared in the flash flood in Chamoli district, Uttarakhand Chief Secretary OM Prakash said.

The Indo-Tibetan Border Police (ITBP) said that there was some cloudburst or breaching of the reservoir at around 10 a.m. which resulted in the flooding in Dhauliganga -- one of the six source streams of the Ganges river. The 85 km river meets the Alaknanda River at Vishnuprayag at the base of Joshimath mountain in Uttarakhand.

Several labourers working at the Rishi Ganga hydroelectric power project were feared missing after a glacier broke.

A dam of the Tapovan power project was breached and feared to have been washed away.

ITBP and State Disaster Response Force (SDRF) personnel have been rushed to the affected areas to evacuate stranded people.

"Casualties feared. Hundreds of ITBP men rushed for rescue," the ITBP said.

Uttarakhand Chief Minister Trivendra Singh Rawat has convened an emergency meeting to take stock of the situation and to supervise rescue and relief operations.

Though the impact of the disaster may not be felt in Rishikesh and Haridwar, the towns have been put on alert.

A government spokesman said that there was not much human habitation at the site where the glacier broke but a number of power projects have been hit.

The government has also appealed to the people not to venture near the Ganga river.

(With inputs from IANS)