Six of the seven fatalities in Arkansas were caused when uprooted trees smashed into houses, National Weather Service meteorologist John Robinson said.
The trees were falling through houses, Robinson said, adding that he could not recall a time in recent memory when so many fatalities occurred because of fallen trees in Arkansas.
In Oklahoma, two elderly sisters were killed when a tornado hit the double-wide mobile home they occupied, according to school board President Bennie Evans.
Among the dead in Arkansas Friday were two boys, ages 6 and 7, and an 18-month-old girl. The seven-year-old and his mother were killed after a tree fell on their house in Little Rock.
"All I heard was a boom boom," said a neighbor, Jennifer McShane, while surveying the destruction that left the mother and her seven-year-old son dead.
At least four tornadoes were also reported in Alabama Friday and more storms were expected tonight, officials said.
Art Faulkner, director of the Alabama Emergency Management Agency, noted the state has several large events this weekend, including sports events at the University of Alabama and Auburn University, and a major NASCAR race at Talladega expecting more than 100,000 fans. "This is causing us to do some extra planning," Faulkner said.
The Talladega Superspeedway alerted fans on its web site to watch the weather and take necessary precautions.
A senior citizen in Sumter County, Alabama was hospitalized after a tree fell on her house, collapsing the roof and ceiling and pinning her down, said Sumter County Emergency Management Agency director Margaret Bishop-Gulley.
And local officials reported severe structural damage in Jackson, Miss., with lines down and roofs off. An 18-wheel semi-trailer truck flipped over on I-20, shutting down the highway. There have been no fatalities reported, though eight people have been injured, one critically, authorities said.
"It was like a bomb went off," said one man in Clinton, Miss., north of Jackson, who did not wish to be identified. His home was destroyed when a tornado passed through the area north of Jackson.
There were severe storms running from western Tennessee into Illinois early Friday evening, but they are expected to dissipate Friday night, said Rich Thompson, a lead forecaster at the National Weather Service's Storm Prediction Center in Norman, Okla.
The main tornado threat will continue overnight across Alabama and Georgia and the same weather system will continue Saturday when it moves into the Carolinas, Thompson said.
"We have another beefed up severe weather threat in the Carolinas and southern Virginia," Thompson said.
Tornadoes kill about 70 people in the United States each year.