The attempt to intercept supercell thunderstorms and tornadoes from as close a distance as possible is known as storm chasing. The prevalence of flat terrain and a scarcity of trees combine with a climatology rich in spectacular and violent weather to make the Great Plains the optimal arena for storm chasing. Each spring, people from all corners of the country and beyond visit "Tornado Alley," an area of the Great Plains stretching from North Texas to Nebraska that is the breeding ground of more tornadoes per area than anywhere in the world, to storm chase. In addition to meteorological researchers, amateur weather enthusiasts, photographers, and videographers chase storms as a hobby, and emergency management "storm spotters" and television news crews chase to provide early warnings to the public.
Storm chasing was formally begun by a handful of scientists at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma, in the mid-1970s to obtain ground truth information in support of the development of weather radar. Storm chasing is extremely hazardous, especially when attempted by those without adequate meteorological training and experience, but the recent swell of attention given the endeavor by the media and the popularity of the Hollywood movie Twister (1996) have led to its dramatic increase as a recreational pursuit. Nationally televised programs regularly take viewers on virtual chases by following research teams and other chasers around the Plains each storm season. Storm-chasing tour companies now take vanloads of paying storm tourists on weeklong voyages in search of storms. Customers come from all backgrounds, and "chase vacations" in the Great Plains have become popular with weather enthusiasts from as far away as Europe and Japan.
Large-scale, research-oriented storm intercept projects also became more numerous in the late 1990s as meteorologists sought to improve warning technologies and understand tornado genesis. Field intercept projects of note include the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX), an ongoing multimillion-dollar research project begun in 1994 and headquartered at NSSL. VORTEX utilizes four to ten vehicles equipped with Mobile Mesonets, an array of sensors mounted on car tops that measure and record weather data very near and around tornadoes. Mobile weather balloon units, video and photogrammetry crews, and radar-equipped "hurricane hunter" aircraft are sometimes used.
Despite their relative frequency on the Plains, tornadoes are still rare events. Even the most experienced and schooled chasers face poor odds of success. Forecasts must be made hours before a tornado touches down, and it is common for chases to cover more than 1,000 miles in a day to and from a "target area." An intercept rate of one tornado witnessed per ten chases is considered a respectable average. In spite of these odds, scientific storm chasing has resulted in the collection of valuable weather data. The success of such field research operations coupled with the high profile storm chasing has gained from media coverage of recent tornado events such as the 1999 Oklahoma City outbreak has stirred widespread fascination with violent weather and made storm chasing an activity likely to remain part of Great Plains science and recreation.
Matthew D. Biddle University of Oklahoma
Bedard, Richard. In the Shadow of the Tornado. Norman OK: Gilco Publishing, 1996.
Bluestein, Howard. Tornado Alley: Monster Storms of the Plains. New York: Oxford University Press, 1999.