The morning after a tornado destroyed more than 300 houses and businesses in and around Oklahoma City (search), firefighters went from one wrecked home to another Friday and spray-painted a big, red X on each roof if no one was trapped.

There were a lot of Xs: Grateful authorities said that remarkably, the twister that carved a 19-mile path through the most densely populated part of the state did not kill a single person.

"We were lucky, basically," said Gary Bird, deputy fire chief in this southern suburb. "We had warning from the National Weather Service (search), and Moore had replaced and upgraded all of its warning sirens, so that helped a lot. People pay a lot more attention."

The state insurance commissioner estimated damage at more than $100 million. But in a week where tornadoes killed 42 people in Missouri, Tennessee, Kansas and Illinois, officials here were counting their blessings.

"It's amazing to me that we didn't lose lives," Gov. Brad Henry said after walking through devastated neighborhoods in Moore (search).

More than 100 people were treated for injuries after the tornado, but only 21 remained hospitalized Friday, said Paul O'Leary, a spokesman for Oklahoma City's ambulance service. At least three were in critical condition.

The tornado ripped through southern Oklahoma City with winds the National Weather Service measured at about 200 mph.

Blaring tornado sirens and TV and radio bulletins provided 10 to 20 minutes' warning in most cases, enough time for thousands of people to scramble into cellars, closets and safe rooms and pull mattresses over their heads before the twister peeled off roofs, blew away walls and uprooted trees Thursday afternoon.

Mary Pace and her husband, E.O., scrambled into a neighbor's cellar when the sirens went off in Moore.

"It boomed just like a big explosion," said Mary Pace, 76. "It looks like a bomb hit, too."

Their red brick house was missing its roof and two walls. The rest of the structure was a mess of insulation, tar paper, roofing and clothes, but she and her 80-year-old husband were not hurt.

Carmelita Jackson took shelter in a hall closet, then had to dig her way out from under a pile of bricks, boards and drywall.

"My life flashed before my eyes," she said. "It was more instinct. You didn't think about where to hide; you just did it."

It was the third twister to hit Moore in six years.

"I just can't imagine why it keeps coming down the same path," said Shearon Cunningham, standing outside her daughter's home, which had caved-in walls and no roof. "Every day in May and June you live on pins and needles."

About 50 homes and 10 businesses were heavily damaged or destroyed in Oklahoma City. In nearby Choctaw, nearly 100 homes were damaged and 10 to 15 were destroyed, fire officials said.

The heaviest damage was in Moore, where the tornado chewed up a path a quarter-mile wide and 3 miles long. Bird said 300 homes and 35 businesses were destroyed.

Chain saws were fired up throughout Moore as workers cut away trees that had been uprooted by the tornado and dropped on homes.

Jim and Frances Clark sat on lawn chairs in their front yard, waiting for their insurance agent. Their roof was blown off and a neighbor's washing machine was hurled through their garage roof and landed on their car.

"We'll start trying to pick up as soon as the insurance man tells us what to do," Frances Clark said. "Homes can always be replaced."

For some, the twister rekindled memories of the May 3, 1999, tornado that ripped through the Oklahoma City area and killed 44 people.

Frances Clark said she hid in the same spot for both tornadoes.

"It is Tornado Alley, so you get used to it," she said.

In the South, floodwaters blamed for at least one death began receding in Tennessee, Alabama and Georgia. Hundreds of people fled their homes this week because of high water on the Tennessee River and other streams.

The Tennessee reached its highest level since 1973, damaging nearly 500 buildings and causing millions of dollars in damage in Chattanooga, Tenn. Some 300 people left West Point, Ga., 75 miles southwest of Atlanta, as the Chattahoochee River reached its highest level since at least 1961.

Police in Chattanooga found the body of a man in a flooded tire lot. In nearby East Ridge, some of the more than 1,000 evacuees were returning to their houses, apartments and a retirement center.

"A lot of the water has receded. It's like somebody has pulled the cork out of the drain," Deputy Fire Chief Ken Gann said.