TUSCALOOSA, Ala. - A wave of tornado-spawning storms strafed the South America on Wednesday, splintering buildings across hard-hit Alabama and killing at least 77 people in four states.

Some 61 people died in Alabama alone, including 15 in Tuscaloosa when a massive tornado barreled through the area. Sections of the city that's home to the University of Alabama have been destroyed, the mayor said, and the city's infrastructure was devastated.

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Farther north, a nuclear power plant west of Huntsville lost power and was operating on diesel generators. In Mississippi, 11 deaths were reported, four people were killed in Georgia and one in Tennessee.

In Tuscaloosa, 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. A hospital there said its emergency room had admitted about 100 people, but had treated some 400. Charts weren't even started for many patients because so many people were coming in at once. By midnight, only staff and patients were allowed inside.

"What we faced today was massive damage on a scale we have not seen in Tuscaloosa in quite some time," Mayor Walter Maddox told reporters, adding that he expected his city's death toll to rise.

The storm system spread destruction Tuesday night and Wednesday from Texas to Virginia, and it was forecast to hit the Carolinas next before moving northeast.

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.

"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.

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 dozens of students and locals were staying at a 125-bed shelter in the campus recreation center.

Volunteers and staff were providing food and water to people like 29-year-old civil engineering graduate student Kenyona Pierce.

"I really don't know if I have a home to go to," she said

Maddox said authorities were having trouble communicating, and 1,400 National Guard soldiers were being deployed around the state. The flashing lights of emergency vehicles could be seen on darkened streets all over town, and some were using winches to remove flipped vehicles from the roadside.

In a commercial district near the university, students with flashlights checked out the damage. Signs were blown down in front of restaurants, businesses were unrecognizable and sirens whaled off and on throughout the night.

At Stephanie's Flowers, owner Bronson Englebert used the headlights from two delivery vans to see what valuables he could remove the valuables. He said he closed early, which was a good thing. The storm blew out the front of his store, pulled down the ceiling and shattered the windows, leaving only the curtains flapping in the breeze and the steel siding rattling.

"It even blew out the back wall, and I've got bricks on top of two delivery vans now," Englebert said.

A group of students stopped to help Englebert, and carried out items like computers and printers and putting them in his van.

"They've been awfully good to me so far," Englebert said.

Brian Sanders, the manager of an oil change shop, brought his daughters to DCH Regional Medical Center because he felt they'd be safe there. He said his business had been leveled.

"I can't believe we walked away," he said.

Storms also struck Birmingham, felling numerous trees that impeded emergency responders and those trying to leave hard-hit areas. Surrounding Jefferson County reported 11 deaths; another hard-hit area was Walker County with eight deaths. The rest of the deaths were scattered around the state, emergency officials said.

The Browns Ferry nuclear power plant lost offsite power, and the Tennessee Valley Authority-owned plant had to use seven diesel generators to power the plant's three units. The Nuclear Regulatory Commission said the safety systems have operated as needed and the emergency event was classified as the lowest of four levels.

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

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 morning when a towering sweetgum tree fell onto his tent as he shielded his young daughter with his body, said Kim Korthuis, a supervisory ranger 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.

By late Wednesday, the state's 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.

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."