twister slams downtown ATLANTA

ATLANTA, Georgia (CNN) -- A tornado ripped through downtown Atlanta on Friday night, rippling the roof of the Georgia Dome during a college basketball game, shattering windows and ripping roofs from buildings before tearing into several residential neighborhoods.

Debris and broken glass litter the street outside CNN Center in Atlanta, Georgia.

Officials at two Atlanta hospitals said they'd treated at least 15 people for injuries -- two of them firefighters.

Hospital officials called one of the injuries "life threatening" but said most were superficial cuts and bruises.

The National Weather Service had issued a tornado warning for the area, in effect until 10 p.m. The storm came through at about 9:45 p.m.

Inside CNN Center, water poured through damage in the ceiling into the building's atrium. Glass shattered, and parts of the building filled with dust.

Watch coverage of damage to CNN Center »

Timothy Wood, 30, of Cumming, Georgia, took refuge from rain at Philips Arena. "First thing I saw were cups then I saw larger objects -- like parts of Philips Arena were coming off and being blown into the street," Wood said.

"People were just running to the closest place of safety they could find. Me and another guy were struggling trying to close the door to Philips and we saw another guy across the way and we waved him over. It probably lasted about two minutes. We went back outside after it was over and there were trees that were actually broken," he said.

Virtually all of the windows facing Centennial Olympic Park on the Omni Hotel, which is attached to CNN Center, were shattered. One employee said visitors to the hotel were being evacuated.

Windows also were shattered in the CNN.com newsroom. CNN's library was also damaged. Watch survey of damage to Omni Hotel »

Outside the building, debris littered the streets and billboards collapsed onto parked cars. Centennial Olympic Park was also severely damaged.