Mark Kelley of the Jefferson County EMA is reporting a total of 11 deaths, up from a single death disclosed there earlier in the day.
Elsewhere in Alabama, severe weather has claimed 39 lives, including 15 in the hard-hit college town of Tuscaloosa.
Also on Wednesday, storms killed 11 in Mississippi, two in Georgia and one in Tennessee.
The death toll may rise, with Alabama's governor saying there could be a half-dozen more deaths. Tuscaloosa's mayor said sections of the city that's home to the University of Alabama had been destroyed by a massive tornado. News footage showed paramedics lifting a child out of a flattened home there, with many neighboring buildings in the city of more than 83,000 also reduced to rubble.
"The city experienced widespread damage from a tornado that cut a path of destruction deep into the heart of the city," Mayor Walter Maddox said in a statement.
The storm system spread destruction Tuesday night and Wednesday from Texas to Georgia. Falling trees were blamed for deaths in several states, including a father struck while protecting his daughter at a Mississippi campsite.
The system was forecast to hit Georgia, Tennessee and Kentucky on Wednesday night and then the Carolinas. Another storm system was also dumping rain on New York.
"Today is the day you want to be careful," said Greg Carbin of the National Weather Service's Storm Prediction Center in Oklahoma.
Gov. Robert Bentley declared a state of emergency in Alabama, the scene of at least six deaths, and he said officials were trying to confirm reports of six more. One woman died when her mobile home was torn to shreds, and a second woman was trapped under a mobile home elsewhere. Falling trees or limbs also killed a woman in her house, a man standing outside and a motorist in separate locations. Another death was reported by Maddox.
Around Tuscaloosa, traffic was snarled Wednesday night by downed trees and power lines, and some drivers abandoned their cars in medians. University officials said there didn't appear to be significant damage on campus, and it was opening its student recreation center as a shelter.
In both Mississippi and Alabama numerous felled trees blocked roads, impeding emergency responders and those trying to leave hard-hit areas.
Austin Ransdell and a friend had to hike out of their neighborhood south of Birmingham after the house where he was living was crushed by four trees. No one was hurt.
As he walked away from the wreckage, trees and power lines crisscrossed residential streets, and police cars and utility trucks blocked a main highway.
"The house was destroyed. We couldn't stay in it. Water pipes broke; it was flooding the basement," he said. "We had people coming in telling us another storm was coming in about four or five hours, so we just packed up."
Not far away, Craig Branch was stunned by the damage.
"Every street to get into our general subdivision was blocked off. Power lines are down; trees are all over the road. I've never seen anything like that before," he said
The weather service didn't immediately confirm that the damage was caused by tornadoes, but forecasters had issued several tornado warnings and said winds blew as hard as 70 mph, just short of hurricane force. Meteorologists found themselves in the path of tornado and had to evacuate their Huntsville office.
In Choctaw County, Miss., a Louisiana police officer was killed Wednesday morning when a towering sweetgum tree fell onto his tent as he shielded his young daughter with his body, said Kim Korthuis, a supervisor with the National Park Service. The girl wasn't hurt.
The 9-year-old girl was brought to a motorhome about 100 feet away where campsite volunteer Greg Maier was staying with his wife, Maier said. He went back to check on the father and found him dead.
"She wasn't hurt, just scared and soaking wet," Maier said.
Her father, Lt. Wade Sharp, had been with the Covington Police Department for 19 years.
"He was a hell of an investigator," said Capt. Jack West, his colleague in Louisiana.
Also in Mississippi, a man was crushed in his mobile home when a tree fell during the storm, a truck driver died after hitting a downed tree on a state highway and a member of a county road crew was killed when he was struck by a tree they were removing. Four more Mississippi storm deaths were reported late Wednesday, but the circustances weren't immediately clear. The governor also made an emergency declaration for much of the state.
The Arkansas Department of Emergency Management confirmed early Wednesday that another person died in a storm in Sharp County. Officials said the person was in a home near Arkansas Highway 230 but didn't know exactly how the person died.
Severe storms in northwest Georgia downed trees, blew out windows in a hospital and tore off part of a school roof. Much of north and central Georgia was bracing for another round of thunderstorms and a tornado watch was issued.
In eastern Tennessee, a woman was killed by falling trees in her trailer in Chattanooga. Just outside the city in Tiftonia, what appeared to be a tornado also struck at the base of the tourist peak Lookout Mountain.
Tops were snapped off trees and insulation and metal roof panels littered the ground. Police officers walked down the street, spray-painting symbols on houses they had checked for people who might be inside.
Mary Ann Bowman, 42, stood watching from her driveway as huge tractors moved downed trees in the street. She had rushed home from work to find windows shattered at her house, and her grandmother's house next door shredded. The 91-year-old woman wasn't home at the time.
"When I pulled up I just started crying," Bowman said.
Many around the region were happy to survive unscathed even if their houses didn't. In Choctaw County, Miss., 31-year-old Melanie Cade patched holes in her roof after it was heavily damaged overnight.
Cade was in bed with her three children when the storm hit.
"The room lit up, even though the power was out. Stuff was blowing into the house, like leaves and bark. Rain was coming in sideways," she said, adding that they managed to scurry into a bathroom.
"I didn't care what happened to the house," Cade said. "I was just glad we got out of there."
Reeves reported from Birmingham. Associated Press writers Jamie Stengle in Edom, Texas, Andrew DeMillo and Nomaan Merchant in Vilonia, Ark., Jack Elliott Jr. in Jackson, Miss., Bill Fuller and Alan Sayre in New Orleans, Dorie Turner in Atlanta, Bill Poovey in Chattanooga, Tenn., and Terry Wallace in Dallas contributed to this report.