Emergency crews were assessing damage on Thursday after a storm system packing high winds and spawning tornadoes tore through the southern and central United States, killing at least 11 people and injuring scores. Mississippi declared a state of emergency in areas pounded by tornadoes.
The stormy weather scrambled holiday plans in Florida while northeastern states expected unseasonably warm temperatures. Forecasts indicated New York City would be warmer than Los Angeles on Christmas Day.
More than 20 tornadoes were reported on Wednesday in Arkansas, Illinois, Indiana, Mississippi and Tennessee, according to the National Weather Service.
A large tornado struck a 100-mile stretch of northern Mississippi on Wednesday, demolishing or heavily damaging dozens of homes and other buildings in a six-county area before plowing into Tennessee, authorities said.
"The devastation is just unreal," Master Sergeant Ray Hall, a spokesman for the Mississippi Highway Patrol, told CNN.
Mississippi Governor Phil Bryant declared a state of emergency in areas affected by the storm, saying 14 tornadoes had touched down in the state. Bryant said seven people were killed.
"Everybody is pulling together here in Mississippi today to help respond to this disaster," Bryant said on CNN.
Six people died in Tennessee and an 18-year-old woman was killed in Arkansas when a tree crashed into her house, authorities said.
Emergency crews in Mississippi, Alabama, and Tennessee were searching for several people reported missing and assessing damage from the destructive winds.
Isolated severe thunderstorms were expected to continue early Thursday from Louisiana through Kentucky, up to Washington, D.C. and eastern Pennsylvania, the National Weather Service said.
An 18-year-old Arkansas woman died and a toddler was injured when a tree crashed into a house after being uprooted by powerful winds, according to emergency officials.
More than 100 million Americans were expected to travel during the holiday period beginning on Wednesday, 91 million of them by car, according to the American Automobile Association.