LUCKNOW, India (AP) — Indian authorities launched a search operation Saturday after part of a mountain glacier broke, sending a massive flood of water, mud and debris into areas below and damaging homes and a power plant.

A portion of Nanda Devi glacier broke off in Tapovan area of the northern state of Uttarakhand on Sunday morning, damaging the Rishiganga hydel power project, said police official Rishi Khemka.

At least 150 people were working at the plant and their fate was unknown, the Press Trust of India news agency reported, citing Ridhim Aggarwal, an official of the State Disaster Response Force.

Ravi Bejaria, a government spokesman, said some houses were also damaged in the flooding.

Officials said the glacier breaking sent water trapped behind it as well as mud and other debris surging down the mountain and into other bodies of water. An advisory was issued urging people living on the banks of the Alaknanda River to move to safer places immediately.

Several teams of rescuers were rushed to the affected area, officials said.

In 2013, more than 1,000 people were killed in Uttarakhand heavy rains triggered landslides and floods, washing away thousands of houses and roads and cutting communication links in many parts of the state.