(CNN) -- A powerful storm system punched through the Midwest before daylight Wednesday, spawning tornadoes, killing at least nine and leaving trails of destruction, including in the resort city of Branson, Missouri.
At least 100 people were hurt, authorities said Wednesday.
Other possible tornadoes were possible Wednesday evening as the storm pushed toward the Mid-Atlantic region, according to CNN meteorologist Sean Morris.
Such activity was possible in northern Alabama, extreme north Georgia, southern and eastern Kentucky, northern Mississippi, western North Carolina and much of Tennessee, he said.
In addition to possible tornadoes, the storm itself will carry thunderstorm winds as strong as 80 mph.
Among the hardest hit cities was Harrisburg, Illinois, where at least six people were killed, according to the governor's office. The dead included four women and two men.
The tornado that hit Harrisburg was preliminarily rated an EF-4 -- the second most powerful on the rating scale -- according to the National Weather Service. A report indicated the tornado had winds estimated at 170 mph.
The twister appeared to have been on the ground for several miles, said Mayor Eric Gregg. The path of destruction was about three or four football fields wide, he said.
The scene in the southern part of Harrisburg, in southern Illinois, was one of debris and collapsed houses. Commercial and residential buildings were crushed. A tractor-trailer could be seen laying on its side, off the highway.
"When the sirens were going on this morning ... it was eerily quiet. I had a gut feeling something was wrong," Gregg told reporters.
"We will rebuild this city. This will make us stronger." Gregg said.
According to the Sheriff's Office, some 100 people were injured and between 250 and 300 houses were damaged or destroyed. Some 25 businesses were also damaged or destroyed, the sheriff's office said.
Among the structures hit was the Harrisburg Medical Center.
The tornado sheared off part of the building's southern wall, leaving several patients' rooms exposed, as well as some offices, said hospital worker Jane Harper.
Luckily, hospital staff had enough time to move those patients to the better-protected center of the building before the twister struck, she said.
Several counties in Kentucky reported storm damage, but no fatalities were immediately reported.
"We can't confirm there was a tornado, but we have reported sightings, and they have actually seen some video of what appears to be a tornado," Kentucky Emergency Management spokesman Buddy Rogers said.
That possible tornado struck in McCracken County, where five injuries were reported, one critical, Rogers said.
At least six counties in the state reported structure damage. The Kentucky National Guard activated 30 soldiers in LaRue County to assist.
A shaken and bruised Steven Vaught of Greenville recounted how he and his two dogs tumbled when his trailer rolled several times down the hill. They all survived.
"It's a joy to be here. I don't know how I'm here," Vaught told CNN Nashville affiliate WKRN. "The good Lord just didn't call me. It wasn't my time."
An apparent tornado near Cassville, Missouri, left one person dead, the Barry County Sheriff's Office said. That person was thrown out of a mobile home, the sheriff's office said.
One death each has been reported in Buffalo and Puxico, Missouri officials said.
The country music showcase of Branson also was hit.
"I woke up this morning and looked outside and saw houses were destroyed," said Steven Scharmanzer in Branson. "I've never seen anything like this in the 20 years I've lived here."
Gov. Jay Nixon, who declared a state of emergency, said the damage there was in at least the tens of millions, but there were no reported deaths. "We are confident that Branson will be back bigger and better than ever," the governor said.
An EF-2 tornado smashed at least seven miles of the city's commercial strip, leaving 33 people hurt, most with minor to moderate injuries.
The city's convention center and an attached Hilton were damaged, as was a portion of Branson Landing, a large shopping and entertainment complex.
City Administator Dean Kruithof said about five or six of the city's roughly 40 theaters were damaged.
"We have so many people who want crews in here to clean up, who want to start rebuilding," Kruithof said.
Kansas was hit Tuesday night, and Gov. Sam Brownback declared a state of emergency for the tiny town of Harveyville, about 20 miles southwest of Topeka. Emergency teams combed the community to assess damage after the National Weather Service confirmed a tornado had struck the city.
Some homes and a church were damaged, and there were numerous reports of trees and power lines down throughout the area, according to the Kansas Adjutant General's Department.
At least one person was critically injured and transported to a hospital in Topeka, while four others were briefly trapped in a structure.
Even when the system didn't spawn tornadoes, it wreaked havoc: The town of Pittsburg, Kansas, experienced straight-line winds up to 120 mph Tuesday, creating a one-mile path of damage that touched upon a motel, power poles and several trees, the weather service said.
There were also reports of a suspected tornado touchdown in Kansas' Reno County, near Hutchinson, and another in central Nebraska.
CNN's Logan Burruss, Kara Devlin, Josh Levs and Michael Martinez contributed to this report.