At least nine people have died in the eastern United States, including eight in Kentucky, as powerful storms brought flooding and exceptionally powerful winds, downing trees and cutting power, local officials announced Sunday.

Brutally cold weather is expected to hit much of the country later in the week.

"I'm heartbroken to share we've lost at least 8 people to this storm," Kentucky Governor Andy Beshear said on X. "And remember, the severe weather continues."

He said the number of fatalities was likely to increase.

In addition, one person died in the southern city of Atlanta, Georgia. The victim was killed when an "extremely large" tree fell on his house early Sunday, local fire official Scott Powell told local media.

Most of the dead in Kentucky, Beshear said in an earlier news conference, drowned when trapped in their vehicles by fast-rising floodwaters. The victims included a mother and her child.

The governor, who has declared a state of emergency, urged people to stay off the roads.

Beshear said more than 1,000 people had been rescued by first responders within 24 hours.

The storm was blowing up from the South and into the US Northeast, a region struck in recent weeks by a succession of extreme cold, snow, rain and powerful winds. 

More than 500,000 customers were without power Sunday from the South through New York state, according to monitoring website poweroutage.us. 

The National Weather Service predicted the center of the country would be hit this week by a mass of extremely cold Arctic air, bringing record temperatures that could hit brutal lows — even -60 degrees Fahrenheit (-51 degrees celsius) in the Plains states near the Canadian border.