Story highlights Six to 13 tornadoes touched down in north Texas, the NWS says

Dallas mayor: "We dodged a big bullet"

Hundreds of buildings are damaged and hundreds of flights are canceled

"It was like 'The Wizard of Oz,' " says one witness

Cleanup efforts began in Texas on Tuesday after tornadoes ripped through the Dallas-Fort Worth area, tossing tractor-trailers like toys, forcing airlines to cancel flights and causing widespread damage.

In Lancaster, Texas, south of Dallas, roofs were stripped to bare plywood and houses were speared by flying two-by-fours. About 300 buildings were damaged, according to the city's mayor. A citywide curfew was put in place, and a shelter was opened.

"It was like 'The Wizard of Oz,' " said Gwen Dabbs, who wasn't able to make it to an interior room before the storm blew her windows out. She huddled in a corner of her living room covered with blankets as the tornado passed.

"My body is sore from being in the corner. But I don't have not a cut, not a scratch, and I'm so thankful. Thank you, Lord," she said.

CNN affiliate WFAA broadcast striking video of area damage, showing tractor-trailers being lifted and flipped like matchsticks. Ominous clouds filled the skies, making it as dark as night.

"The pictures that you're seeing and that I'm seeing are just horrific. We've got reports of a number of injuries, but no reports of fatalities at the present time," said Lt. Gov. David Dewhurst.

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As many as 13 tornadoes might have touched down in north Texas on Tuesday, said Jesse Moore, a meteorologist with the National Weather Service in Dallas-Fort Worth.

"Somewhere between six and 13. I know that sounds like a big range, but until we actually go out and do the survey, the number is just approximate," he said. Teams are preparing to assess the damage on Wednesday.

The severe weather affected flights and aircraft at area airports.

More than 110 aircraft at Dallas-Fort Worth International Airport sustained various degrees of hail damage, the airport said. It reported airlines canceled 400 departures, and more than three dozen incoming flights were diverted to other airports because of the storm.

Southwest Airlines, meanwhile, canceled more than 40 flights at Dallas Love Field, while American Airlines canceled all flights through Tuesday evening at Dallas-Fort Worth, one of the world's busiest airports.

The announcement, made via Twitter, was likely to affect American flights in other parts of the country. In all, American and its American Eagle partner airline canceled 234 outbound flights, according to a statement from American.

By Tuesday evening, more than 47,000 homes and businesses in north Texas were without power, said a spokeswoman for Oncor Electric Delivery.

Jonathan Cook said he was in a bank in south Fort Worth when the storm rolled in and he decided to leave. He went to a nearby gas station, where he ran into a friend whose window had been blown out and a National Weather Service worker with a radio who told them tornadoes were touching down nearby.

"A girl said 'Look up.' And there were two funnel clouds that touched down about an eighth of a mile up from us, and debris was flying and we were trying to decide where to go.

"About that time, she said, 'Look behind us' -- and a third tornado formed behind us, but hadn't touched down," Cook said. "And about three minutes after that, the sirens started sounding."

Photos: Photos: Tornadoes tear through Texas Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Cambrie Thornton, left, and Royal Thornton sit outside their destroyed home Wednesday, April 4, after a tornado struck on Tuesday in Forney, Texas. Multiple tornadoes touched down across the Dallas/Fort Worth area, causing extensive damage. Hide Caption 1 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Between six and 13 tornadoes might have touched down in north Texas on Tuesday, the National Weather Service in Dallas-Fort Worth said. The number is an estimate pending a survey and damage assessment. Hide Caption 2 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Mike Enochs, left, and Gary Enochs salvage a baby crib from Mike Enochs' destroyed home. There are no reports of deaths so far, according to the mayors of Dallas and Arlington. Hide Caption 3 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Volunteers use a small tractor to clear debris in front of a damaged house. Hide Caption 4 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Nelda Vines sits in a chair in the front lawn of a home while waiting for several family members who were visiting a tornado-ravaged neighborhood. Hide Caption 5 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – This home in Forney is a single example of the widespread devastation caused by Tuesday's storms. Hide Caption 6 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – A tornado touches down in Lancaster, Texas, on Tuesday. Multiple tornadoes ripped through the Dallas-Fort Worth area, causing extensive damage. Hide Caption 7 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – April Bridges looks at the remains of a house destroyed by a tornado in Arlington, Texas. Hide Caption 8 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – A woman holds a few personal items after a tornado destroyed her home in Arlington. Hide Caption 9 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – IReporter William Lawrence Meador captured the damage that the powerful storm left behind after it hit Grand Prairie, Texas. Hide Caption 10 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – A police officer in Arlington returns a dog to David Lowe after it was rescued from the rubble of his daughter's home. Hide Caption 11 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Residents search for personal belongings after a tornado destroyed their home in Arlington. Hide Caption 12 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – A man in Arlington works to clean up his garage after it was damaged by a tornado. Hide Caption 13 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Patricia Daugherty searches through her belongings after her home was destroyed. Hide Caption 14 of 15 Photos: Photos: Tornadoes tear through Texas Tornadoes tear through Texas – Arlington's mayor signed a disaster declaration to help cope with the destruction. Hide Caption 15 of 15

Among the most dramatic images of the day were from a freight truck depot on the south side of Dallas, where one twister flung semitrailers high in the air and hundreds of feet from their parking spots.

The lot is owned by Wisconsin-based Schneider National Trucking Company. Company spokeswoman Janet Bonkowski said there were no injuries at the facility and no damage to the building, "but significant damage to the equipment that was in our yard."

A tractor weighs 20,000 pounds. An empty trailer weighs 14,000 pounds, while a full one weighs about 46,000, the company said.

CNN meteorologist Sean Morris estimated the tornadoes that moved through the Dallas-Forth Worth area were EF1 or EF2 twisters, at their strongest.

"This is fairly weak in terms of tornadoes, but we saw the awesome power of the twisters as they lifted the trailers several hundred feet in the air," he said.

Damage was also reported in Kennedale and Arlington, Texas. The mayor of the latter city signed a disaster declaration to help cope with the destruction.

"It's extensive damage," said Tiara Richard, a spokeswoman for Arlington police. No major injuries have been reported so far, but affected areas were still being searched for people who may be trapped, she said.

Tarrant County spokesman Mark Flake said about 40 homes in Arlington sustained moderate damage. The Cowboys football stadium emerged almost unscathed, according to its general manager.

In Kennedale, a large water main broke, and several people were injured, said city spokeswoman Amethyst Cirmo, though she could not immediately confirm how many. The city's police chief, however, said there were no reports of deaths or injuries thus far. A community center was opened to residents displaced by the storm.

Dallas County Sheriff Lupe Valdez said the area was hit by "a series of tornadoes" that inflicted heavy damage on some of the southern suburbs.

"Our officers are going to several locations right now," Valdez said. She said deputies were en route to some of the hardest hit areas to prevent looting, amid reports "that some of that has already started."

"We have our hands full. There are already a lot of situations where we have to go out and help," she said.

But all told, damage from the storm could have been much worse, said Dallas Mayor Mike Rawlings.

"The big headline is that we dodged a big bullet," he said. "We're saddened by the damage the system did, but we've got nobody that's dead and no significant injures. It really is a miracle."