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Doppler radar measures 318 mph wind in tornado By Jack Williams, USATODAY.com AP Moore City, Okla., after the May 3, 1999 tornado. Scientists measured the fastest wind speed ever recorded, 318 mph, in one of the tornadoes that hit the suburbs of Oklahoma City on May 3, 1999. The record-setting wind occurred about 7 p.m. near Moore, where the tornado killed four people and destroyed about 250 houses. Joshua Wurman of the University of Oklahoma says he and his research team were about a half-mile away when they measured the record wind. Wurman says the actual speed in the part of the tornado measured could have been nine or 10 mph slower or faster than 318 mph. Wurman's group used a truck-mounted Doppler radar, one of the two used in the Doppler On Wheels (DOW) project at the University of Oklahoma in Norman. (Related: Doppler on Wheels program). The fastest speed previously measured was 286 mph clocked by a portable Doppler radar April 26, 1991, in a tornado near Red Rock, Okla. 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. (Related: The Fujita tornado scale). Wurman says the 318 mph measurement was the "third most interesting thing" he and the others involved in the case accomplished on May 3. The most interesting and important was capturing detailed radar images of the formation of the super cell thunderstorm that eventually spawned the tornado and then of the tornado. The second most interesting set of data was about 20 minutes of radar images of another large tornado north of Oklahoma city, that didn't hit any towns of cities later that night. This storm was the first ever intercepted by scientists after dark, Wurman said. Chasers stop at dark because a tornado they can't see could hit them. But, the truck-mounted Doppler radar can be used to keep track of tornadoes even when the truck is moving. The team has enough experience that the trust the radar to keep them away from twisters that they can't see. 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." (Note: Originally published in 1999 and re-published in 2003 with minor editing.)