In June 1956, David Hoadley was a teenager when a storm passed through his home town of Bismarck, North Dakota, which is at the northernmost end of America's Tornado Alley.
Hoadley was in a local cinema at the time. “I heard the thunder outside really loud,” he recalled. “My father came down after it happened and said there is a better show outside.”
The storm knocked out most power in Bismarck. Driving in the dark with his father, they came across fallen, broken power lines dancing on a patch of wet grass creating bright, brilliant sparks in the darkness.
“It was kind of eerie and exciting,” he said. “I decided I needed to learn more about it. I started studying, forecasting and taking pictures.”
Hoadley (76) has been chasing tornadoes across the Great Plains of the US ever since. Next year is his 60th year of chasing. (He skipped one year, 1966, to go on honeymoon.) He takes three or four short trips during peak storm season, from late April to mid-June, travelling state to state, hoping to catch one of those violent rotating columns of air that cause so much damage across the central US.
Killed five
The region is in peak tornado season now. Up to 25 twisters tore through the southern part of the alley last weekend, killing five in
Texas
and
Arkansas
, including a couple in west Arkansas. Their 18-month-old daughter was pulled unharmed from the wreckage of their mobile home.
Tornado Alley runs from northern Texas through Oklahoma into Kansas, Nebraska and Iowa and on up into the Dakotas. The area is prone to twisters because the jet stream flies through a naturally occurring topographical corridor created by the Rocky Mountains to the west, drawing moisture up from the Gulf of Mexico to the south.
Tornadoes form in supercells, rotating thunderstorms that last long periods and create up-drafts called mesocyclones or small-scale cyclones.
Twisters require thermal dynamic instability in the atmosphere, meaning it has to be warm near the ground and cold aloft. The jet stream produces “strong vertical wind sheer” , in which the wind speed and direction at the bottom is different from up above. This creates those spectacular twisting funnels.
Early in the year there is strong “sheer”, but not enough moisture from the Gulf to create as many tornadoes.
“During the summer we have the maximum heat near the ground and maximum amount of moisture near the surface,” said meteorologist Howie Bluestein of the University of Oklahoma. “Early in the season we have the strongest winds aloft. Somewhere in between, around May, we have enough of both to get tornadoes.”
Hoadley has recorded 232 tornadoes in more than half century of chasing storms. The retired US government administrator, who lives in Falls Church, Virginia, is considered the “father” of storm-chasing and has the “longest storm-chasing career”, according to the Guinness World Records.
He had a close shave once. While he was chasing in Nebraska in June 1993, a tornado turned 180 degrees in his direction. Hoadley and his daughter dived into a ditch. The F3 storm, with wind speeds of 158 to 206 miles an hour, wiped out two nearby farms.
The biggest twister he has ever seen was on May 31st, 2013 in El Reno, Oklahoma, which became an “F5” with wind speeds reaching 300 miles per hour. It killed three veteran chasers and five others.
Unphotogenic
Hoadley prefers not to get close. His interest is in observing the whole storm structure and he likes to use a wide-angled lens. Getting too near a tornado means the photography is not as photogenic.
“It is mostly bragging rights to say I was within a quarter mile or it passed within a hundred yards of me,” he said. “It’s not the kind of chasing most veterans like myself enjoy. It’s not what we call a ‘good chase’.”
Hoadley chases because, unlike other natural wonders that are always there (Giant Redwoods, the Rockies), tornadoes are dynamic, changing rapidly. A storm builds, peaks in a couple of hours and then is gone.
Bluestein and his researchers stay a safe distance away when they are out gathering data every year from March to June. In Oklahoma in 1995, a small tornado surprised them. They didn’t have time to collect data so they just filmed the twister, about the width of a two-lane road, as it moved silently in front of them.
“It was very ethereal-looking,” Bluestein recalled. “When you see the tornado from a distance, if it has a funnel cloud; it is very sharply delineated. But when you are close, it looks like a ghost, a vaporous ghost that is moving across.”