Deadly storm system sweeps across South

A storm system forecasters called "particularly dangerous" killed four people Wednesday, and officials were searching for missing residents into the night.

States from Louisiana to Illinois were under a tornado watch.

Tornadoes touched down in Indiana and Mississippi, where three were killed. The springlike storms packing strong winds killed two more in Tennessee.

A tree blew over onto a house in Arkansas, killing an 18-year-old woman and trapping a 1-year-old child inside, authorities said. Rescuers pulled the toddler safely from the home.

A 7-year-old boy died in Holly Springs, Mississippi, when the storm picked up and tossed the car he was riding in, officials said. Police there said several homes were blown off their foundations.

Slabs of metal were tangled in drooping power lines, dangling precariously alongside the road, and the smell of freshly overturned dirt and trees lingered in the air as emergency crews tended to downed power lines.

In Benton County, Mississippi where two deaths occurred and at least two people are missing, search-and-rescue crews were doing a house-by-house search to make sure residents were accounted for.

A tornado damaged or destroyed at least 20 homes in the northwest part of the Mississippi. 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.

After 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 EF scale categorizes tornado damage from EF-0 — light damage — to EF — inconceivable damage. An EF-1 tornado causes moderate damage.

The biggest threat for tornadoes was in a region of 3.7 million people in Mississippi, Tennessee and Arkansas and parts of Missouri, Illinois and Kentucky, according to the national Storm Prediction Center in Oklahoma. The center issued a "particularly dangerous situation" alert for the first time since June 2014, when two massive EF4 twisters devastated a rural Nebraska town, killing two people.

Elsewhere, skiers on the slopes out West got a fresh taste of powder and most people in the Northeast enjoyed spring-like temperatures as they finished up last-minute Christmas shopping.

Only about half of the nation, mostly in the West, should expect the possibility of a white Christmas.

In parts of Georgia, including Atlanta, a flood watch was posted through Friday evening as more than 4 inches was expected, the National Weather Service said.

The threat of severe weather just before Christmas is unusual, but not unprecedented, said Greg Carbin, a meteorologist at the national Storm Prediction Center.

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."

Wire services