318-mph Storm Wind Fastest Ever
By Jack Williams
Scientists said Monday that they had measured the fastest wind speed ever recorded, 318 mph, during a tornado May 3 in the suburbs of Oklahoma City.
The record-setting wind occurred about 7 p.m. near Moore, where the tornado killed four people and destroyed about 250 houses.
The wind speed was measured with a truck-mounted Doppler radar.
The fastest speed previously measured was 286 mph clocked by a portable Doppler radar April 26, 1991, in a tornado near Red Rock, Okla.
Joshua Wurman of the University of Oklahoma says he and his research team were about a half-mile away when the tornado was born.
The 318-mph speed would put the tornado only 1 mph below an F-6 on the 0-to-6 Fujita scale. No tornado has ever been classified an F-6.
Because direct measurements of tornado winds are rare, meteorologists have used the severity of damage to classify tornadoes. Conventional wind instruments cannot withstand powerful twisters, and scientists are just beginning to make close-up measurements with Doppler radars.
Wurman says the 318-mph winds probably were a couple of hundred feet above the ground, not at ground level where the twister was doing the damage that later led the National Weather Service to classify the storm as an F-5.
"We don't know this was the strongest tornado ever, just that no other had ever been measured with faster winds," Wurman says.
Winds that powerful can rip pavement from roads, grass from the ground and freight cars from train tracks.
After taking the measurement, the Doppler radar trucks followed the tornado to nearby Del City, "where it died very quickly," Wurman says.
"We went through the damage a minute or two after the tornado. It was rough driving."
Bob Sheets, former director of the National Hurricane Center, says that "the ability to make such measurements is quite a breakthrough." The methods will "help solve the mysteries of both tornadoes and hurricanes."