National Geographic News: NATIONALGEOGRAPHIC.COM/NEWS
 

 

Storm Chasers Face the Powerful Forces of Nature

Herb Stein
University of Oklahoma
June 11, 2001
 
Tornadoes are actually rare in any given area, even in "tornado alley." That is why storm chasers have to log many miles in pursuit of their subject.



The window of opportunity for research is small, usually only about eight weeks a year. That is why we find ourselves taking chances on road trips even if there is only a slight chance a tornado will occur somewhere in the region.

A classic example is our one-day road trip to Des Moines, Iowa. We left Norman, Oklahoma, at dawn to intercept storms in Eastern Nebraska. As we drove north, however, the part of the storms that appeared to present the greatest risk moved eastward.

Our efforts were rewarded with one marginally interesting storm and a long drive home.

Our next road trip, in New Mexico and Texas, was four long days. New Mexico is not an area where we usually would look for tornadoes to happen. But the high terrain in the northeast corner of the state has all the ingredients for rotating storms, known as "supercells," which develop into the most powerful tornadoes.

A scarcity of roads and the prevalence of hills that blocked our radar scans posed a challenge to our ability to intercept storms that were building.

All was for naught, however, as the storm we were monitoring rotated, but did not grow into a tornado. Instead of acquiring scientific data, we got a stunning view of the beautiful storm dying beneath the sun [see photo].

Luck Left Behind

Two days later found us fighting trees in eastern Oklahoma, and the day seemed poised for an outbreak of tornadoes.

Luck—more than skill and experience—is a storm chaser's best friend on days when tornadoes seem likely to occur. On days that are ripe for tornado outbreaks, there may be several strong storms to choose from. Sometimes, deciding which one to pursue is just a coin toss.

In Oklahoma, as it turns out, luck was not on our side. The storm of the day was just beyond our reach.

From radar, we could see that the storm was developing into a tornado only about 20 miles east of us. But it was quickly moving away.

Given the choice of roads available to us and the speeds at which both the storm and our radar vans were moving, we could not intercept it. We had to settle instead for a robust supercell at the heels of the eastern storm.

As we moved toward the western supercell, the storm was not building into a tornado. We tried to get ahead of it, but the storm caught up with us as we were driving east, pelting us with a heavy core of rain and small hailstones.

Already battered and disappointed, we then had to drive through the path of damage that was left by a tornado that built from the eastern storm.

Building Strength

Once out ahead, we set up our radar trucks anticipating that the storm might produce a tornado. I got out of the truck to watch the swirling clouds that were approaching slowly from the west.

The base of the storm had all the features that suggested it would develop into a storm, including a rotating pendulous cloud called a "wall cloud." Joshua Wurman, who was operating the radar, alerted us that a tornado would form.

As he had predicted, a small tornado formed about a mile north of us. It was brief and weak, however. There was only a small funnel at the cloud base, although other tornado chasers watching from the north of us saw a small cloud of debris beneath the funnel in a nearby field.

The storm moved east, and our pursuit resumed. Unfortunately, the only road available to us was again at the core of heavy rain and hail.

As we approached the storm, we had to drive through the "hook"—the part of the storm that wraps around the supercell's rotating core and is usually full of rain, hail, and strong winds. The closer we got to the center of rotation where the tornado could form, the stronger the winds and the more blinding the rain became.

Leaves and small branches were being ripped from the trees and flew sideways. Wurman saw on radar what appeared to be a small tornado in the process of forming just a mile straight ahead in the road we were travelling on.

Rocked by Heavy Winds

We pushed ahead, trying to escape the rain so we could witness the tornado, when suddenly the wind and debris picked up force. We heard a loud "thud" as something airborne hit the side of our truck.

Branches and small articles were moving horizontally across the road, and the heavy rain—also moving horizontally—whited out our view of anything outside the truck.

We stopped, and I could feel the truck being blown forward by the powerful winds. The rain was so intense it interfered with the radar signals. We measured the nearby winds, and found they were moving up to 100 miles an hour.

As our 13-ton truck rocked in the winds, it was filled with a low-frequency noise as the wind rushed across our equipment. I sat back in the seat shielding myself as much as possible from the window, because airborne debris can be deadly.

My mouth went completely dry as I contemplated my arrogance in wanting to keep driving into the teeth of the tornado.

After what seemed like an eternity, the winds ebbed. We saw that a telephone pole had been bent over alongside our truck.

We continued forward to the town of Stigler, Oklahoma. Its tornado sirens were blaring. The streets, littered with trees and pieces of sheet metal, were deserted. An old metal lawn chair sat upright in the middle of a road.

The withering storm had peaked, and we had enough excitement for one day. Our hopes of acquiring "perfect data" would have to wait for another chase.
 

© 1996-2008 National Geographic Society. All rights reserved.