UPDATED STORM CASUALTIES:
TUSCALOOSA, Ala. -- The death toll from severe storms that punished five Southern U.S. states jumped to a staggering 178 after Alabama canvassed its hard-hit counties for a new tally of lives lost.
Alabama's state emergency management agency said early Thursday it had confirmed 128 deaths, up from at least 61 earlier.
Mississippi officials reported 32 dead in that state and Tennessee raised its report to six from one. Another 11 have been killed in Georgia and one in Virginia.
The fierce storms Wednesday spawned tornadoes and winds that wiped out homes and businesses, forced a nuclear power plant to use backup generators and even prompted the evacuation of a National Weather Service office.
The National Weather Service's Storm Prediction Center in Norman, Okla., said it received 137 tornado reports around the regions, including 66 in Alabama and 38 in Mississippi.
One of the hardest-hit areas Wednesday was Tuscaloosa, a city of more than 83,000 and home to the University of Alabama. The city's police and other emergency services were devastated, the mayor said, and at least 15 people were killed and about 100 were in a single hospital.
A massive tornado, caught on video by a news camera on a tower, barreled through the city late Wednesday afternoon, leveling it.
By nightfall, the city was dark. Roads were impassable. Signs were blown down in front of restaurants, businesses were unrecognizable and sirens wailed off and on. Debris littered the streets and sidewalks.
The governors in Alabama, Mississippi and Georgia each issued emergency declarations for parts of their states.
President Barack Obama said he had spoken with Alabama Gov. Robert Bentley and approved his request for emergency federal assistance, including search and rescue assets. About 1,400 National Guard soldiers were being deployed around the state.
"Our hearts go out to all those who have been affected by this devastation, and we commend the heroic efforts of those who have been working tirelessly to respond to this disaster," Obama said in a statement.
Earlier story: BIRMINGHAM, Ala. -- A wave of severe storms laced with tornadoes strafed the South on Wednesday, killing at least 72 people in four states and splintering buildings across swaths of an Alabama university town.
In Alabama alone, 25 people died Wednesday. There were 11 deaths in Mississippi, including a father killed as he tried to shelter his daughter from the storm at a campsite.
Tuscaloosa's mayor said sections of the city that's home to the University of Alabama had been destroyed by a massive tornado, while a hospital there said its emergency room had admitted at least 100 people. News footage showed paramedics lifting a child out of a flattened home, 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. The system was forecast to hit the Carolinas next and then move further northeast.
"Today is the day you want to be careful," said Greg Carbin of the National Weather Service's Storm Prediction Center in Oklahoma.
A state of emergency was declared 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
In Huntsville, Meteorologists found themselves in the path of tornado and had to evacuate the National Weather Service office.
In Choctaw County, Miss., a Louisiana police officer was killed Wednesday 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.
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.
By late Wednesday, the death toll had increased to 11 for the day, said Mississippi Emergency Management Association spokesman Jeff Rent. The governor also made an emergency declaration for much of the state.
Storms also killed two people in Georgia and one in Tennessee on Wednesday. Aside from the deaths on Wednesday, one person was killed by the same storm system late the previous night in Arkansas.
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."