Chasers Intercept Tornado on Final Day of Storm Season
for National Geographic News
|July 5, 2001|
The perfect data set involves positioning the radar trucks at nearly right angles to each other and aiming at the tornadic region of the storm. We wanted to document the entire life cycle from the birth of the tornado, through its mature stage and demise.
This is actually very hard to do. Many times you deploy the trucks in perfect position only to have the storm move away before producing the tornado.
Or you wait a little too long and then the tornado forms before you are in position and you miss its birth.
We have about 40 mature tornado data sets, but up till now obtaining an entire life cycle with both our mobile radar systems, the Dopplers on Wheels (DOWs), has eluded us.
We knew that the 2001 season was about over. Our student staff and leader had other pressing projects to attend to so we were taking our last road trip.
So far this season, the DOWs had already logged around 8,000 miles (13,000 kilometers) and documented five tornadoes in their mature stages. We had high hopes on this, our last chase day of the year.
The day started with several storms, but we were able to weed out the best storm, which was in south-central Kansas. We placed our radar trucks in perfect position and started collecting data.
The supercell storm had all of the textbook structure indicative of tornado formation. We held our breath as we watched and waited for a tornado to form.
Finally, the storm seemed to be getting its act together when a small rain cell formed to its southeast and dumped rain-cooled air into the supercell's inflow. This choked off the supercell's updraft energy and our hopes for an immediate tornado.
We would have to re-deploy farther east in hopes that the storm could reform.
On our second perfect deployment farther east, the storm was organized again and rotating and our chances for a good tornado data set were increasing.
As the dark storm core approached our location, its base was full of dynamic motions. But much to our dismay, the supercell seemed to be cycling down once again and we had to bug out to the east or risk being stuck in an intense core.
After several hours of chasing and patience, would our third deployment be charmed?
We placed our two trucks about ten miles (16 kilometers) apart on the only road options available. The storm would hopefully pass somewhere between the two trucks and produce a tornado as it passed.
Our truck was in position and was collecting data as the storm slowly approached from the west.
Stuck in a Ditch
As the other truck was trying to maneuver into position on a dirt road, it inadvertently became stuck in a ditch! While the crew worked feverishly to free their vehicle, we watched as the storm started to look interesting on our radar screen.
Through perseverance and perspiration, the other crew freed their truck just in time to start collecting data at a critical time.
While we anxiously watched the radar screen, the storm started to produce a tornado.
Although the data appeared to be good, the crews were disappointed because the tornado was completely wrapped up in rain and was obscured from vision.
Anxious Moments as Tornado Approached
This also made for some anxious moments since the tornado was approaching our other truck.
We cautiously watched the tornado's Doppler radar signature for any signs of strengthening winds. But since the tornado remained rather weak, we held the crew in position to keep collecting data.
The weak tornado passed just to the north of their site as it died. The storm was done producing tornadoes.
Even though the tornado was weak and short-lived, it was a tornado and we collected dual-Doppler data through its entire life cycle.
The data will take many months to analyze, but they appeared to be good.
For the rest of the evening, we were treated to a beautiful lightning display signifying the close of our season.
It was unfortunate that our research season had to end. Shortly after the DOWs were parked and their data were downloaded, storm activity was reported from the Midwest and Central Plains. Several days of large tornadoes ensued.
Even though our season was over, we were able to direct some IMAX movie film crews to the right locations. The IMAX teams (partially funded by the National Geographic Society) are trying to capture on film the perfect tornado.
They have filmed several tornadoes, but they will be back next year to try to capture their perfect data set.
Herb Stein is a technician with the Doppler on Wheels program at the University of Oklahoma. The program uses mobile Doppler radar trucks that are designed to collect high-resolution data during the full life cycle of a tornado.
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