Three people were killed and more than 200 were believed to be missing after a flash flood in a river valley in northern India. The flood damaged the Rishiganga hydroelectric station near Raini village in Uttarakhand state, as well as a partially built plant on the Dhauliganga River near Tapovan, police said. Ashok Kumar, the state police chief of Uttrakhand, said that more than 200 workers were missing. "The waters have been controlled in a dam. There is no danger downstream but we are taking precautions," he said. Both the damaged sites belong to the Indian state power utility company, NTPC. The Indo-Tibetan Police Force said that three bodies were recovered near the NTPC Tapovan project, and at least 12 workers who were trapped in a tunnel at the site had been rescued. "There were 50 workers at Rishiganga and there is no information about them," Mr Kumar said. "Some 150 workers were at Tapovan. "There are around 15 to 20 workers trapped inside the tunnel when the floods came." The army and air force have joined the rescue operation. The river is a tributary of the Ganges, running through steep gorges. Although the region is sparsely populated, flash flooding in the area caused hundreds of deaths further downstream in 2013. Authorities said the devastation on Sunday resulted from an avalanche triggered by a glacier breach at about 11am. People living on the banks of the Alaknanda River were asked to leave immediately. “The most disturbing thing is that this is not flood season and there was no warning to those downstream,” Himanshu Thakkar, co-ordinator of the South Asia Network on Dams, Rivers and People, said. MPS Bisht, director of the Uttarakhand Space Application Centre, said that prior to the glacier collapse, there had been a strong discharge of water in the Rishiganga tributary of the Dhauliganga. "There are almost 14 glaciers around the famous Nanda Devi peak, which rises to 7,817 metres. These glaciers supply ice melt water to the Rishiganga," he said.