US deep freeze leaves more than 700,000 without power, thousands of flights canceled

Three deaths were reported in Kentucky, where Governor Andy Beshear, on Saturday, warned residents, "Stay home, stay safe, stay alive."

"I know it's really hard because it's Christmas Eve. But we're having dozens and dozens of accidents," he said in an online briefing. "It's simply not safe."

Blizzard conditions remained on Saturday for Buffalo, New York, and its surrounding county on the edge of Lake Erie in far western New York where 4-to-6 feet of snow will fall by Sunday, the National Weather Service (NWS) said.

The city imposed a driving ban on Friday that remained in effect on Saturday, and all three Buffalo-area border-crossing bridges were closed to inbound traffic from Canada.

Temperatures were forecast to top out on Saturday at just 7 degrees Fahrenheit (minus-13 Celsius) in Pittsburgh, surpassing the city's previous all-time coldest Christmas Eve high of 13 F, set in 1983, the NWS said.

Cities in Georgia and South Carolina - Athens and Charleston - were likewise expected to record their coldest daytime Christmas Eve high temperatures, and Washington, D.C., was forecast to experience its chilliest Dec. 24 since 1989.

The flurry of yuletide temperature records was predicted as a deep freeze sharpened by perilous wind chills enveloped much of the eastern two-thirds of the nation.