On the Trail of Storm Chasers: Scientists Pursue Causes of Tornadoes

by Herb Stein
for National Geographic News
May 21, 2001

Tornadoes are one of the final meteorological frontiers for scientists to conquer. There is a fairly good understanding of "supercells," the rotating thunderstorms responsible for major tornadoes. But knowledge of what actually causes tornado formations still consists only of theories. If the final piece of the puzzle can be found, we may be able to more accurately forecast tornadoes and provide earlier warnings.

How do we learn more about tornadoes? Some scientists try to create them in laboratories or on computers. Without actual data and "ground truth" from actual tornadoes, however, those results are largely speculative. So scientists known as storm chasers go out into the field during tornado season on the Great Plains in the U.S. to observe tornadoes and collect data.

Despite what's suggested by images on the evening news, tornadoes are rare and fleeting. Great effort goes into witnessing them and collecting data.

One method is to use mobile Doppler radar trucks that are designed to collect high-resolution data during the full life cycle of a tornado. I'm a technician with such a program, Doppler on Wheels, at the University of Oklahoma.

When close to a storm, the radar trucks, or DOWs, can view the lowest levels of the storm where tornadoes form. The phenomenon can be seen at a resolution several thousand times higher than that of the National Weather Services radar network. Each truck moves into position to view a tornado from a different angle so the data will be more complete.

Since the University of Oklahoma's project began in 1995, under the leadership of associate professor Joshua Wurman, the DOWs have collected data on dozens of supercell storms and tornadoes.

One notable day was May 3, 1999, when scores of tornadoes—many of them extremely violent—crossed Oklahoma and blew into Kansas. One of the tornadoes monitored by the DOWs ripped through the town of Bridge Creek and moved through the Oklahoma City Metropolitan area. That single tornado grew to a mile wide. It killed about three dozen people and leveled entire neighborhoods.

Collecting data at the outskirts of the metro area, the DOWs measured a peak wind speed of 318 miles per hour. Early warnings issued by the National Weather Service and circulated by the media, along with quick reaction by a storm-educated public, saved many lives.

During the short tornado season, the DOWs work to document as many tornadoes as they can. In subsequent dispatches I'll report on our research efforts to learn more about destructive, yet elusive, tornadoes.



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