At least 18 people are missing after a flood in the Tons River washed away around 20 houses in Uttarakhand's Uttarkashi district on Sunday. The Tons River has been flowing above the danger level in Uttarkashi following heavy rainfall in the past few days. The water breached local markets recently, prompting the administration to issue an alert.

Chief Minister Trivendra Singh Rawat directed the Uttarkashi District Magistrate and Disaster Management Secretary to carry out rescue and evacuation operations and provide relief material to the affected people, news agency ANI reported.

The state government has sent in teams of Indo-Tibetan Border Police (ITBP), National Disaster Response Force (NDRF) and State Disaster Response Fund (SDRF) for rescue operations.

However, incessant rains have severely crippled transportation, making it difficult to reach the spot.

The Gangotri highway, a key road in the region, has been shut down after landslides.

Flash floods and cloudbursts have left people stranded in several areas of the state. Authorities in all districts have ordered schools to remain closed on Monday.

The weather department has predicted widespread rainfall over the next three days in Uttarkashi along with Chamoli, Pithoragarh, Dehradun, Pauri and Nainital districts.

Uttarakhand had been struck by devastating floods in 2013 that killed thousands of people and caused extensive damage.

Extreme rainfall had caused lakes and rivers to burst their banks, inundating towns and villages below.

A government report filed by a panel of experts had said badly managed hydro-power projects were partly to blame for the disaster.

While the official number of deaths was about 900, more than 5,700 people were declared missing, making it the deadliest ever in the mountainous region.

Floods or landslides also washed away or damaged 5,000 roads, 200 bridges and innumerable buildings.