Up to a dozen tornadoes rip through Dallas-Fort Worth By Jon Nielsen and Marice Richter DALLAS (Reuters) - Up to a dozen tornadoes skipped through the densely populated Dallas-Fort Worth area in Texas on Tuesday, ripping apart homes and tossing tractor-trailer trucks into the air, but there were no reports of serious injuries or deaths. National Weather Service meteorologist Jesse Moore said that 10 to 12 tornadoes touched down during a massive storm that brought chaos from high winds, rain and hail to the nation's fourth most populous metropolitan area. Many of the 6.3 million area residents were forced to scramble for safety as the storm bore down during the early afternoon, when schools and workplaces were open. Hundreds of homes and businesses were damaged, some of them extensively, but no one was reported killed or seriously injured. "We've seen roofs blown off, houses totally flattened, tractor-trailers knocked over," Moore said. It was a bad day weather-wise for north Texas. One tornado lifted trucks like toys in the Flying J Truck Plaza in Dallas, said truck driver Michael Glennon, who caught the destruction on his video camera as debris swirled through the air. "The second trailer is ripped to pieces and thrown 50 to 100 feet into the air," he told Reuters. Video broadcast of a truck parking lot showed a row of trailers peeled open and others piled on top of each other. The storm system was moving east into Oklahoma, Arkansas and Louisiana with the potential of producing high winds and more tornadoes on Tuesday evening, Moore said. Sixth-grader Hailey Pellerin said she and other students had just started lunch when teachers quickly herded students back to their classrooms in their southwest Arlington elementary school. "We had to duck and cover for two hours," she said. The students were seated, lined up against a wall in their classrooms and covered their heads. The power went out so it was dark and hot. The tornado passed about 200 yards from the school, her father David Pellerin said. "We were so lucky because it came so close but passed by the two schools my kids attend," said Pellerin, the father of three. In one of the hardest hit areas, Lancaster, the city said tornadoes damaged 300 structures, about half of those severely damaged. Some 110 planes were damaged by hail and 400 flights canceled at Dallas-Fort Worth International Airport, the eighth busiest in the world, stranding thousands of passengers. Another 40 incoming flights were diverted. Southwest Airlines said another 40 flights were canceled in and out of Love Field, the area's second-largest airport. During the height of the storm, witnesses at the airport said the sky turned dark and passengers were herded away from windows and into stairwells and restrooms. "These devastating tornadoes show how quickly Mother Nature can strike in our state," Texas Governor Rick Perry said in a statement urging residents to stay off roads and heed warnings and instructions from officials. The U.S. tornado season has started early this year. Tornadoes have been blamed for 57 deaths so far in 2012 in the Midwest and South, raising concerns that this year would be a repeat of 2011, the deadliest year in nearly a century for the unpredictable storms. In 2011, there were 550 tornado deaths with 316 lives lost on April 27 in five southern states, and a massive tornado that killed 161 people in Joplin, Missouri, on May 22. Tuesday's tornadoes in Texas could prove more costly than a hailstorm nearly a year ago in the Dallas area that caused more than $100 million in insured losses. That April 15, 2011, storm was less damaging in terms of hail and winds. Insurers have already lost as much as $2 billion during the 2012 tornado season, mostly from a record March 2 outbreak. That follows record-breaking losses of $26 billion during the 2011 tornado season. Additional Reporting by Corrie MacLaggan, James Kelleher, Kyle Peterson, Judy Wiley, Ben Berkowitz and Karen Jacobs; Editing by Andrew Stern, Will Dunham and Lisa Shumaker