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In Texas and Louisiana strong winds knocked down trees killing two people. In Oklahoma, snow-covered roads caused an accident that killed one driver.
In Mobile, Ala., a tornado touched down and knocked out power to thousands of people. A major emergency response was under way to access the damage.
In Texas, authorities said high winds knocked over a tree, killing one man near Houston. Investigators said he tried to move another downed tree blocking the road when another one snapped and fell on top of him. Temperatures in the Lone Star State dipped below freezing on Christmas, making it cold enough for flurries to fall north of Dallas.
In Oklahoma, freezing rain is to blame for a 21-car pileup early in the morning that injured 10 people. The accident shut down westbound traffic on Interstate 40 near Oklahoma City.
The severe weather in the Midwest and the South arrived as millions of Americans were traveling for the holidays.
To the East In Maryland, black ice hidden under a layer of snow sent cars slipping and sliding.
Parts of Arkansas also awakened to a white Christmas and more snow was expected in the Ozark Mountains.
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About a dozen counties in Missouri were under a winter storm warning. It kept snow plow operators on stand-by.
In Atlanta, the airport was fogged in, but flights were still able to depart despite the reduced visibility.
The weather delayed flights out of San Francisco by at least an hour. In the Sierra Nevada, a winter storm dumped several feet of fresh powder, adding to last week's snowfall.
Tornadoes in December are not unheard of. The National Weather Service says in 2009, 22 tornados touched down on Christmas Eve along the Gulf Coast. The last deadly twister during the holiday was in Tennessee in 1988.
