At least 11 people were killed, including a young boy, after a spring-like storm system swept across the Southeast.
The storms mixed with unseasonably warm weather, spawning tornadoes that killed people in Mississippi, Tennessee, and Arkansas. Dozens more people were injured.
The youngest victim was a 7-year-old in Holly Springs, Mississippi, who was killed in a van on Highway 7 as storms swept through the town, according to Marshall County Coroner James Anderson. Tree limbs and debris covered the highway Thursday, and emergency crews worked to restore downed power lines.
The storms — which the National Weather Service called a "particularly dangerous situation" for an area that spanned eastern Arkansas, northwest Mississippi, northeast Louisiana and western Tennessee — destroyed homes and caused power outages on Wednesday.
At least seven people died in Mississippi. Four of the deaths were in Benton County, where another person was unaccounted for, officials said. Two were in Marshall County, and the other was in Tippah County.
"It is difficult, particularly this time of year, to see such damage and know that heartbreaks go along with that damage, that families have lost loved ones," Mississippi Gov. Phil Bryant said at a news conference Thursday afternoon. "There's no good side to this, but at least the storm was not in highly populated areas, like a downtown."
Three others were killed in Tennessee, where heavy rain continued to soak the eastern border but was expected to move out of the state later today. A 22-year-old man who was not identified died in Rhea County. In Perry County, Annie Yzaguirre, 69, and Antonio Gomez Yzaguirre, 70, died, Chief Deputy Nick Weems of the Perry County Sherriff's Office told NBC News.
In Atkins, Arkansas, 18-year-old Michaela Remus was killed when a tree crashed into the bedroom she was sharing with her 18-month-old sister. The toddler was taken to a hospital after being safely pulled out of the home by rescuers.
Rusty Russell, 34, a friend of Remus', told NBC News that "she is one of those people that you would never hear a bad word about her. Just a true joy to be around."
Remus died protecting her sister, he said.
"She was laying in bed with her 18-month-old sister. The way that she was laying actually shielded her sister," he said.
More than a dozen tornadoes were reported in Mississippi, and in the town of Clarkdale, hundreds woke up Thursday without homes for the holidays. Planes at a small airport were overturned by wind gusts. There were an unknown number of injuries, Clarksdale Mayor Bill Luckett told the Associated Press, but he said the only reported casualty in his town was a dog killed by storm debris.
"I'm looking at some horrific damage right now," Luckett said. "Sheet metal is wrapped around trees; there are overturned airplanes; a building is just destroyed."
Mulestor Johnson, 67, told the AP that a brutal storm tore his Holly Springs house from its foundation Wednesday. His belongings were strewn everywhere, and trees had crashed through trucks on his property, but no one was hurt.
"This right here is a mess, but I can't complain because we're blessed," he said.
The Mississippi Emergency Management Agency said at least 40 people were injured as the storms moved swiftly across the state. Agency spokesman Greg Flynn said some of the injuries included amputations.
"It's terrible that this happened, especially at Christmas," Pope County Sheriff Shane Jones told the AP.
Meanwhile, in parts of Georgia, including Atlanta, a flood watch was posted through Friday evening. More than 4 inches of rain was expected, according to the National Weather Service.
The rainy, gusty conditions — more reminiscent of June than December — spread north into the Midwest. Indiana emergency officials warned that outdoor Christmas decorations could turn into dangerous missiles and advised residents not to bother putting up inflatable decorations.
Even Santa Claus was canceled, as officials in Woodland Township, Ohio, called off their holiday light display Wednesday night at the town's rec center,NBC station WDTN of Dayton reported. Unfortunately for the town's children, it was supposed to have marked St. Nicholas' final appearance at this year's festival.
Even worse: "We're really concerned about the additional storms yet to come," said Danielle Banks, a meteorologist for The Weather Channel.
The unseasonable weather is yet another manifestation of the unusually strong El Niño setting up shop off the West Coast, meteorologists told NBC News. Much of the eastern half of the country will spend a Christmas Day with temperatures in the 70s.
And it couldn't come at a worse time, with nearly 1 in 3 of all Americans traveling this week for Christmas.
"We are seeing more than 100 million people will be traveling overall," Robert Sinclair, a spokesman for AAA, told NBC News. "That's the first time we've ever hit that record."
According to airline tracker FlightAware.com, more than 2,060 U.S. flights were delayed as of Thursday morning, and nearly 600 had been canceled.
This story originally appeared on NBCNews.com