An immense, powerful cyclone packing destructive winds hammered eastern India on Sunday, forcing more than 500,000 people to evacuate and sending seawater surging inland. The number of casualties and the extent of damage from Cyclone Phailin won’t become clear until after daybreak, officials said.

The storm, which made landfall early Saturday night near the town of Golpalpur in Orissa state, was expected to cause large-scale power and communications outages and shut down road and rail links, officials said. It is also expected to cause extensive damage to crops.

Officials in Orissa and Andhra Pradesh state have been stockpiling food supplies and setting up shelters. The Indian military has put some of its forces on alert and readied trucks, transport planes and helicopters for relief operations.

Roads were all but empty Saturday as high waves pounded the Orissa coastline. Seawater pushed inland, swamping villages where many people survive as subsistence farmers and live in mud-and-thatch huts.

As the cyclone swept across the Bay of Bengal toward the Indian coast Saturday, satellite images showed its spinning tails covering an area larger than France.

With some of the world’s warmest waters, the Indian Ocean is considered a cyclone hot spot, and some of the deadliest storms in recent history have come through the Bay of Bengal, including a 1999 cyclone that hit Orissa and killed 10,000 people.

U.S. forecasters had repeatedly warned that Phailin would be immense. “If it’s not a record, it’s really, really close,” University of Miami hurricane researcher Brian McNoldy said. “You really don’t get storms stronger than this anywhere in the world, ever.”

McNoldy said Phailin is nearly the size of Hurricane Katrina, which killed 1,200 people in 2005 and caused devastating flooding in New Orleans, and has the wind power of 1992’s Hurricane Andrew, which packed 165 mph winds at landfall in Miami.

In Berhampur, a town about seven miles inland from where the eye of the storm hit, the sky blackened quickly, with heavy winds and rains pelting the empty streets.

“My parents have been calling me regularly. They are worried,” said Hemant Pati, 27, who was holed up in a Berhampur hotel with 15 other people from the coastal town hit first by the storm.

The hotel manager said he would bar the doors against anyone trying to enter, saying there would be food, water and electricity from generators only for guests of the Hotel Jyoti Residency. “Nobody can come inside, and nobody can go out,” Shaik Nisaruddin said.

A few hours before it hit land, the eye of the storm collapsed, spreading hurricane-force winds over a larger area and giving it a “bigger damage footprint,” said Jeff Masters, meteorology director at Weather Underground, part of the Weather Channel Cos.

“This is a remarkably strong storm. It’s going to carry hurricane-force winds inland for about 12 hours, which is quite unusual,” Masters said.

— Associated Press