April 4, 2012

Rare twin supercells unleashed at least 18 tornadoes on the Dallas-Forth Worth metropolitan region. (A supercell is a massive low-pressure center characterized by a very large cumulonimbus cloud and long-lasting thunderstorm, often producing numerous and violent tornadoes.) The National Weather Service characterized the storms as among the most destructive in the area’s history. Twisters flung several massive semi-tractor trailers into the air and tossed a school bus across a road and into a diner. Hundreds of houses were severely damaged or leveled in the Dallas suburbs of Arlington, Lancaster, and Forney. In Arlington, an entire wing of a nursing home collapsed, forcing the evacuation of dozens of residents. The storms left thousands of households without electric power. Miraculously, there were no fatalities and relatively few injuries.

A supercell thunderstorm is a violent storm dominated by a single gigantic cell--a weather system made up of storm clouds and the winds associated with them. Rain and hail may fall for hours. (National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation)

At the Dallas-Ft. Worth International Airport, all flights were canceled, stranding thousands of passengers. Baseball-size hail pounded planes on the tarmac waiting for take-off. “The noise of ice . . . hitting the aluminum exterior of a 757 was as deafening as it was frightening,” noted one passenger.

Although the tornado season has just started in the United States, meteorologists point out that there have already been dozens of destructive twisters from Illinois to Texas.

Additional World Book articles:

• Safety (During a tornado)
• Storm