Atlanta, Crews hauled broken glass and furniture out of downtown streets Saturday and homeowners surveyed damage caused by a possible tornado that caught residents and basketball fans by surprise.
More thunderstorms headed across northern Alabama toward the city Saturday. "We're bracing for another round of whatever mother nature throws at us," said Lisa Janak of the state emergency management agency.
The National Weather Service posted a tornado watch for a large area of Georgia, including the Atlanta area, plus portions of South Carolina and Alabama, and a warning was issued for a part of northern Alabama.
At least 27 people were hurt Friday night, though no injuries were believed to be life-threatening.
All downtown events scheduled for Saturday were canceled, including the St. Patrick's Day parade.
"It's a mess," Janak said.
Mayor Shirley Franklin said the storm was "what we now know was a tornado." National Weather Service officials continued to say only that a "possible tornado" hit around 9:40 p.m. as a thunderstorm roared through with wind up to 60 mph.
That was just 10 minutes after the weather service issued a tornado warning.
Weather service investigators planned to examine the wreckage Saturday to determine whether a tornado caused it.
"It does look like it from what we're seeing," said Trisha Palmer, a weather service meteorologist in nearby Peachtree City. "The radar sign is very indicative of a tornado but we've got to get on the ground to make sure it wasn't strong winds."
Palmer said there had been only a "light risk" in the area Friday for thunderstorms capable of producing strong tornadoes and very large hail. In contrast, the risk was rated as moderate Saturday north Georgia and upstate South Carolina.
The storm smashed hundreds of skyscraper windows, blew furniture and luggage out of hotel rooms, crumbled part of an apartment building and rattled a packed sports arena.
Streets around the Georgia Dome, Phillips Arena, the CNN Center and Centennial Olympic Park were littered with broken glass, downed power lines, crumbled bricks, insulation and the occasional office chair. Billboards collapsed onto parked cars.
CNN said its headquarters building suffered ceiling damage that allowed water to pour into the atrium, and windows were shattered in the CNN.com newsroom and the company's library. A water line inside the building broke, turning a staircase into a waterfall.
"It was crazy. There was a lot of windows breaking and stuff falling," said Terrence Evans, a valet who was about to park a car at the Omni Hotel when the storm twister hit.
Although a tornado warning was issued, there was no announcement of the approaching storm for the 18,000 fans inside the Georgia Dome for the Southeastern Conference basketball tournament. The first sign was rumbling and the rippling of the fabric roof. Catwalks swayed and insulation rained down on players during overtime of the Mississippi State-Alabama game, sending fans fleeing toward the exits and the teams to their locker rooms.
"I thought it was a tornado or a terrorist attack," said Mississippi State guard Ben Hansbrough, whose team won 69-67 after an hourlong delay under a roof with at least two visible tears. A later game between Georgia and Kentucky was postponed. SEC officials said the tournament's remaining games would be played at Georgia Tech.
"Ironically, the guy behind me got a phone call saying there was a tornado warning," fan Lisa Lynn said. "And in two seconds, we heard the noise and things started to shake. It was creepy."
Power was knocked out to about 19,000 customers.
A loft apartment building had severe damage to one corner and appeared to have major roof damage. Property manager Darlys Walker said there was one minor injury.
Taylor Morris, 29, who lives near the lofts, said he and his girlfriend took shelter in the bathroom.
"The whole house was shaking," he said. "We didn't know what was going on."
Fire Capt. Bill May said a vacant building also collapsed, with no apparent injuries.
Grady Memorial Hospital, the city's large public hospital where many of the injured were taken, had broken windows but was operating as usual.
In East Atlanta, downed trees, debris and power lines were strewn in the streets.
Melody and Brad Sorrells were home in their living room with their two children when the storm hit, and the huge pine in their front yard crash into their house.
"I saw it falling and we ran into the back bedrooms in the closet," Melody Sorrels said. "I feel sick."
The National Oceanic and Atmospheric Association said the last tornado to hit a major city's downtown was on Aug. 12, 2004, in Jacksonville, Fla. Downtown tornadoes have also struck Fort Worth, Texas; Salt Lake City; Little Rock, Ark.; and Nashville, Tenn., in the past decade.
If confirmed, the tornado would be the first on record in downtown Atlanta, said Smith, the meteorologist. The last tornado to strike inside the city was in 1975, and it hit the governor's mansion north of downtown, he said.
Associated Press writers Errin Haines, Daniel Yee and John Amis and AP Sports Writer Paul Newberry contributed to this report.