At least 14 people were killed in three states across the South after a strong system of storms tore through just as final preparations for Christmas celebrations were under way.

Unseasonably warm weather Wednesday helped spawn twisters from Arkansas to Michigan. The line of springlike storms continued marching east Thursday, dumping torrential rain that flooded roads in Alabama and caused a mudslide in the mountains of Georgia.

Authorities confirmed seven deaths in Mississippi, including that of a 7-year-old boy who was in a car that was swept up and tossed by a storm. Dozens more were injured, some seriously, said Greg Flynn, spokesman for the Mississippi Emergency Management Agency.

Tennessee emergency management officials said in a statement Thursday night that three more people in the state were confirmed dead in the storms.

The statement described the victims as a 19-year-old female and two 22-year-old males. Officials said they died in Maury County. The statement said that no further details are available.

The latest deaths bring the total killed in the Tennessee storms to six. The previous deaths in Tennessee were a 70-year-old male and a 69-year-old female in Perry County, and a 22-year-old male in Rhea County.

One person was killed in Arkansas.

Search teams combed damaged homes and businesses for people still missing on Thursday, a hunt made complicated because so many had left for the holidays.

In Linden, Tennessee, Tony Goodwin ducked into a storm shelter with seven others as the storm passed. He emerged to find his house had been knocked off its foundation and down the hill.

He managed to climb inside and fetch some Christmas gifts that had been under his tree. Goodwin’s neighbors weren’t so fortunate. Two people in one home were killed.

“It makes you thankful to be alive with your family,” he told the Associated Press. “It’s what Christmas is all about.”

The storms also triggered a mudslide on a mountain in north Georgia’s Fannin County, dumped up to 10 inches of rain across parts of southeast Alabama and caused hundreds of flight delays for travelers trying to get home for Christmas.

A wide swath of Alabama’s Coffee County received as much as 10 inches of rain, and a foot of rain was recorded north of Enterprise. Emergency officials say two roads in Chambers County collapsed because of rain, causing natural gas leaks.

A 7-year-old boy died in Holly Springs, Miss., when the storm picked up and tossed the car he was riding in, officials said. Marshall County Coroner James Anderson says the boy’s relatives in the car with him were taken to a nearby hospital for treatment.

Greg Flynn, a spokesman for the Mississippi Emergency management Agency, reported more than 40 injuries in six counties.

A tornado also damaged or destroyed at least 20 homes in the northwest part of the state. Clarksdale Mayor Bill Luckett said the only confirmed casualty was a dog killed by storm debris. Planes at a small airport overturned and an unknown number of people were injured.

“I’m looking at some horrific damage right now,” the mayor told the Associated Press. “Sheet metal is wrapped around trees; there are overturned airplanes; a building is just destroyed.”

Television images showed the tornado appeared to be on the ground for more than 10 minutes. Interstate 55 was closed in both directions as the tornado approached, the Mississippi Highway Patrol said.

About 120 miles east of the tornado, Brandi Holland, a convenience store clerk in Tupelo, Mississippi, said people were reminded of a tornado that damaged or destroyed more than 2,000 homes and businesses in April 2014.

“They’re opening all our tornado shelters because they say there’s an 80 percent chance of a tornado today,” Holland said.

In Arkansas, Pope County Sheriff Shane Jones said 18-year-old Michaela Remus was sleeping in a bedroom with her 1 1/2-year-old sister in the house near Atkins, about 65 miles northwest of Little Rock, when winds uprooted the tree that crashed through the roof, killing the teen. Rescuers pulled the toddler safely from the home.

“It’s terrible that this happened, especially at Christmas,” Jones said.

In Indiana, an an EF-1 tornado struck the south Indianapolis suburb of Greenwood, television stations showed pictures of damage, including a portion of a roof blown off a veterinary office.

The threat of severe weather just before Christmas is unusual, but not unprecedented, Storm Prediction Center meteorologist Greg Carbin told the Associated Press.

Twisters hit southeast Mississippi exactly a year ago, killing five people and injuring dozens of others. On Christmas Day in 2012, a storm system spawned several tornadoes, damaging homes from Texas to Alabama.

Emergency officials in Tennessee worried that powerful winds could turn holiday yard decorations into projectiles, the same way gusts can fling patio furniture in springtime storms, said Marty Clements, director of the Madison County Emergency Management Agency in Jackson, the state’s largest city between Memphis and Nashville.

“If you go through these neighborhoods, there are a lot of people very proud of what they’ve put out and they’ve got stuff everywhere — all these ornaments and deer and everything else,” Clements said. “They’re not manufactured to withstand that kind of wind speed, so they become almost like little missiles.”

The national Storm Prediction Center in Oklahoma issued a “particularly dangerous situation” alert for the first time since June 2014, when two massive EF-4 twisters devastated a rural Nebraska town, killing two people. Center meteorologist Matt Mosier says a preliminary report showed that at least 14 tornadoes touched down in Mississippi.

The Associated Press contributed to this report.