Up to a dozen powerful tornadoes have touched down in the densely populated Dallas-Fort Worth area of the US state of Texas.
High winds tossed articulated lorries into the air, uprooted trees and grounded planes.
Local media reported that 17 people were injured in the storms.
Ten to 12 tornadoes touched down during a massive storm that brought chaos from high winds, rain and hail to the country’s fourth most populous metropolitan area, according to the US National Weather Service.
Many of the area's 6.3m residents were forced to scramble for safety as the storm bore down during the early afternoon, when schools and workplaces were open.
Seven people were injured in the suburb of Arlington, police said. Most suffered only minor injuries but one person hit by a falling tree is in a critical condition.
In one of the hardest hit areas south of Dallas, Lancaster, tornadoes damaged 300 structures.
Authorities were amazed that no-one was killed given the intensity of the storm, the number of tornadoes and the population density of the area.
"We dodged a big bullet ... It really is a miracle," Dallas Mayor Mike Rawlings said in an interview on CNN.
The survival rate from a tornado is higher during the daylight hours because people are more likely to hear or see the warnings and take cover, meteorologists said.
Some 110 planes were damaged by hail and 400 flights cancelled at Dallas-Fort Worth International Airport, the eighth busiest in the world, stranding thousands of passengers. Another 40 incoming flights were diverted.
The US 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.
