Updated 10:51 p.m.
(CBS/AP) DALLAS - Tornadoes raked the Dallas area Tuesday, crumbling a wing of a nursing home, peeling roofs from dozens of homes and spiraling big-rig trailers into the air like footballs. More than a dozen injuries were reported.
Baseball-sized hail punched holes through car roofs, and a Red Cross spokeswoman warned the breadth of the destruction may not be cleared until well into Wednesday, reports CBS affiliate KTVT in Dallas. The mayors of Arlington and Lancaster declared a state of disaster following the storm strike
Overturned cars left streets unnavigable and flattened trucks clogged highway shoulders. Preliminary estimates were that six to 12 twisters had touched down in North Texas, senior National Weather Service meteorologist Eric Martello said. But firm numbers would only come after survey teams checked damage Wednesday, he said.
(Above, watch the CBS Evening News report on the tornadoes)
In suburban Dallas, Lancaster police officer Paul Beck said 10 people were injured, two of them severely. Three people were injured in Arlington, including two residents of a nursing home who were taken to a hospital with minor injuries after swirling winds clipped the building, city assistant fire chief Jim Self said.
"Of course the windows were flying out, and my sister is paralyzed, so I had to get someone to help me get her in a wheelchair to get her out of the room," said Joy Johnston, who was visiting her 79-year-old sister at the Green Oaks Nursing and Rehabilitation Center. "It was terribly loud."
Dallas-Fort Worth International Airport canceled hundreds of flights and diverted others heading its way. Among the most stunning video was an industrial section of Dallas, where rows of empty tractor-trailers crumpled like soda cans littered a parking lot.
"The officers were watching the tornadoes form and drop," Kennedale police Chief Tommy Williams said. "It was pretty active for a while."
The confirmed tornadoes touched down near Royce City and Silver Springs, said National Weather Service meteorologist Matt Bishop.
April is the peak of the tornado season that runs from March until June. Bishop said Tuesday's storms suggest that "we're on pace to be above normal."
Johnston said her sister was taken to the hospital because of her delicate health. Another resident at the nursing home, Louella Curtis, 92, said workers roused her out of bed and put her in the hall.
"The hallways were all jammed," Johnston said. "Everyone was trying to help each other to make a path for others. I'd say everybody was out of their rooms within 20 minutes."
(Above, watch footage of the tornadoes touching down)
Most of Dallas was spared the full wrath of the storm. Yet in Lancaster, television helicopters panned over exposed homes without roofs and flattened buildings. Broken sheets of plywood blanketed lawns and covered rooftops.
A pastor at one Lancaster church saw debris swirling in the wind, then herded more than 30 children, some as young as newborns, into a windowless room to ride out the storm. Nearby at the church's school, about 60 more children hid in another windowless room near the women's bathroom.
An entire wall of Cedar Valley Christian Academy wound up being taken out in the storm. Pastor Glenn Young said he didn't know when the school might re-open.
"I'm a little concerned," Young said. "This is our livelihood."
Residents could be seen walking down the street with firefighters and peering into homes, looking at the damage after the storm passed.
Devlin Norwood said he was at his Lancaster home when he heard the storm sirens. He said he made a quick trip to a nearby store when he saw the funnel-shaped tornado lower, kick up debris and head toward his neighborhood.
"I didn't see any damage until I got back home. We had trees destroyed, fences down, boards down, boards penetrating the roof and the house, shingles damaged," said Norwood, 50, an accountant and graduate student.
The storm pushed cars into fences and toppled trees. Branches and limbs scattered across lawns and residential streets, and in one driveway, a tow-behind RV was left torn apart and crumpled.
"Obviously we're going to have a lot of assessments to make when this is done," Dallas County spokeswoman Maria Arita said.
American Airlines canceled more than 450 arriving and departing flights at its hub airport by late Tuesday afternoon, and 37 other incoming flights had been diverted to different airports.
DFW Airport spokesman David Magana said more than 110 planes were damaged by hail. It wasn't clear how many belonged to American Airlines, but American and American Eagle had pulled 101 planes out of service for hail-damage inspections.
Flights also were canceled at Dallas Love Field, which is a big base for Southwest Airlines. That airline canceled more than 45 flights in and out of the airport by Tuesday evening.
Meteorologists said the storms were the result of a slow-moving storm system centered over northern New Mexico.