[Update 5:13 p.m. ET] The storm system has settled down from severe levels as it moves east into the Carolinas. Further updates on Wednesday's weather and its aftermath will appear at this link.
[Update 4:48 p.m. ET] All tornado warnings in the Southeast have expired, the National Weather Service says.
[Update 4:43 p.m. ET] Georgia Gov. Nathan Deal has declared a state of emergency in Bartow and Gordon counties, where a tornado caused heavy damage earlier today. The declaration makes state resources immediately available to the two counties, Deal said.
[Update 4:17 p.m. ET] Tornado warnings are currently in effect in these counties:
In Georgia: Crawford, Lamar, Lee, Monroe, Talbot, Taylor, Terrell, Upson
In South Carolina: Greenville, Oconee, Pickens
In North Carolina: Transylvania
[Updated 4:04 p.m. ET] The National Weather Service has issued a flash flood warning until 9:30 p.m. for Transylvania County, North Carolina, as the storm system pushes east. The service said 3 to 4 inches of rain had already fallen in the Greenville-Spartanburg area, with an additional 1 to 2 inches - and perhaps 5 inches - expected through the evening.
[Updated 3:19 p.m. ET] High school student Matt Davis was home sick from school today, so he and his father went to see the damage from severe storms that rolled through Gallatin, Tennessee, overnight. He sent images to CNN iReport.
"That's right at the front of my neighborhood," Davis, 16, said. "As soon as you turn down one street, it looks like the trees got shredded to pieces. It looks like there's a lane of trees that got torn out. The back of the neighborhood looks like nothing happened," he said.
Nearby, the Fairview Plantation, a historic farm, was heavily damaged, Davis said.
"The plantation was a horse farm. Those (buildings) have been standing there for 100 to 200 years," he said. "It was sad to see those collapsed and caved in."
Weather damage in your area? If you can do so safely, send photos or video to iReport.
[Updated at 2:39 p.m. ET] There has been another reported tornado in Mountaintown, Georgia, in Gilmer County, according to the National Weather Service, which now has a tornado watch in effect till 8 p.m. for more than 80 Georgia counties.
[Updated at 2:24 p.m. ET] CNN's Mallory Simon reports that several flights out of Atlanta's Hartsfield-Jackson International are canceled, including to airports in North Carolina, Louisiana, Tennessee, Missouri, Mississippi and Alabama. Other flights are delayed, including flights to airports in Washington and Virginia, she said.
[Updated at 2:08 p.m. ET] We now have footage of various storm damage in Tennessee, Indiana and Kentucky.
[Updated at 2:04 p.m. ET] Gail Ralston with Adairsville Towing and Automotive told the Atlanta Journal-Constitution at about 1 p.m. that power is off throughout Adairsville. Motorists were calling for help, but officials were allowing only emergency personnel in the area near where the twister struck, she told the paper.
[Updated at 1:59 p.m. ET] An unidentified truck driver wearing the name tag that reads "Travis" tells CNN affiliate WGCL-TV that he saw cars being thrown in the air before the truck he was driving got flipped on its side. Two firefighters extracted him from the truck, and he said he feels lucky to be alive.
[Updated 1:54 p.m. ET] The National Weather Service is reporting that tornadoes have struck in Indiana and Kentucky.
[Updated at 1:51 p.m. ET] Meteorologists keep citing "bow echoes" in their storm reporting. Curious what it means. The National Weather Service has an explanation here.
[Updated at 1:42 p.m. ET] Kennesaw, Georgia, police are asking that people stay away from Adairsville as officials search for storm victims.
[Posted at 1:36 p.m. ET] There is at least one storm-related death, and numerous cars are overturned on Interstate 75 after a tornado struck Adairsville, Georgia, the National Weather Service reported.
The twister touched down before noon in the city of about 4,600 located roughly midway between Atlanta and Chattanooga, Tennessee, the weather service reported, adding that two other tornadoes were reported in the region - one in east Lindale, another in southeast Calhoun.
Numerous buildings, some with people inside, were damaged in northern Bartow County after a tornado touched down Wednesday morning. One person is dead, and officials believe it's the result of a building collapsing, Bartow County Fire Chief Craig Millsap said.
The Atlanta Journal-Constitution further reported that "dozens" of vehicles were overturned on I-75 in Bartow, and local news reports aired images of scores of cars stopped on the highway. The paper also the tornado leveled a large manufacturing plant in Adiarsville.
All lanes of 75, both northbound and southbound, were blocked at milepost 306 in Georgia, the state's Department of Transportation reported.
Meanwhile, Georgia Power says its reports of outages have been "fairly light."
A reporter for CNN affiliate WSB-TV said he saw the tornado form as he arrived in Adairsville on Wednesday morning. At least one home was leveled, and cars were flipped over, the station reported.
Bartow County police and fire dispatchers told the Journal-Constitution there were injuries and numerous calls of trauma in and around Adairsville before 11:30 a.m. ET, and one call to the fire department reported that a building in Adiairsville was ablaze and five people were trapped inside.
The paper further reported one call involved an overturned car with someone inside. Many roads in the area are impassable, the paper said.
In the north Georgia, there were reports of winds between 20 and 40 mph, with gusts of 35 to 50 mph, the weather service reported.
In Nashville, Tennessee, a man told CNN affiliate WTVF that his wife's uncle was killed when a tree fell on a shed about 3 a.m. Tornado warnings were issued in Middle Tennessee overnight, and CNN affiliate WKRN reported that a possible tornado touched down in Mt. Juliet.
WKRN also reported an overturned 18-wheeler, brush fires, roof damage and trees down in the Mt. Juliet area.
There were also reports of storm damage overnight or Wednesday morning in Alabama, Arkansas, Indiana and Kentucky.FULL STORY