The vans are a jet-flash of white paint as they streak down the turnpike, gunning it to 90 mph.
They're not the police. They're not ambulances. But they're still reacting to the worst nature can throw.
These are storm chasers, part of the tornado paparazzi. This afternoon's bait: a supercell in far western Oklahoma that could spit out an EF2 (that's lingo for a strong tornado on the Enhanced Fujita scale, which measures such storms.)
Highways are increasingly clogged with storm chasers trying to beat each other in a risky race to capture the storms, and some have even been killed. While there's no certain way to estimate how many there are, longtime chasers who crisscross the Midwest put the figure in the thousands, if not tens of thousands. Fifteen years ago, they estimate that number would have been a few hundred.
"It's become a much bigger thing. Because data is available to anybody, you can essentially have live radar data in your vehicle with you for the price of satellite wireless," says Harold Brooks, meteorologist at the National Oceanic and Atmospheric Association's Severe Storms Laboratory in Norman, Okla.
The chasers' motivations vary. Some are scientists hoping to better understand tornadoes. Others are insured tour guides who are paid thousands of dollars to thrust thrill-seekers into harm's way. Many, however, are just adrenaline junkies armed with little more than a fancy cell phone or wireless laptop.
Lucky ones capture a photograph or video and can sell it for $50 or $100 to a TV station or magazine; unlucky ones crash their Jeeps and miss the storm altogether.
"The thrill of the chase. ... That's the excitement," says Tiffany Crumrine, 37. She's part of the pack tracking the EF2, and tired of seeing funnel clouds only on TV.
Any storm on the Great Plains could have as many as 15, 20 or 30 cars following it.
"There's so many chasers, it's difficult to get where you need to go, and that can be a problem," says Greg Forbes, a severe weather expert at The Weather Channel, who often talks to scientists who have run into a mob of chasers that have gotten in the way, ruining a chance to track a storm. "What if a tornado hits something, and there are so many cars around? It makes it difficult for emergency managers to do their jobs."
At least three people have been killed since 1999 while chasing or observing weather for forecasters, according to the National Association of Storm Chasers and Spotters.
Topeka, Kan.-based chaser Scott Blair says he has noticed that some parents take their kids on the chase while others get as close as 100 yards from the twister.
Even the highly trained meteorologists at the Severe Storms Laboratory or the adjacent Storm Prediction Center mostly follow tornadoes from inside those government facilities. At times, a handful of weather geeks go into the field to collect data on how storms form, and even go out after storms hit to determine their severity and reconstruct the path they traveled.
"Nobody has a job as a storm chaser," Brooks says. "Maybe 5 percent of the time ... we would have people here who might be involved in tornado intercept."
One Tuesday at noon the chasers tracking the EF2 hope for a repeat of the more than two dozen twisters that came the day before. Even though two people died in those storms, the rush among the paparazzi is a palpable.
Drivers use two-way radios to spread warnings about speed traps. One driver radios that it's easy to do 10 or 15 mph over the limit in Oklahoma, and brags he can go even faster when chasing storms in Wyoming or Colorado.
Taking a break from the NASCAR-worthy sprint to fill up on gas, Chris Kridler stands by her Honda Element with its "2 OZ" license plate.
She lives in Florida and has visited the gut of Tornado Alley each year since 1997 with just a simple video camera.
To her, storm-chasing has become a dangerous trend among people who watched the movie "Twister" too much. She worries the newer chasers are poorly equipped to handle powerful weather and take risks that experienced storm chasers wouldn't dare.
"(They think), 'I've got to drive into the tornado,'" Kridler says. "And someone's going to get killed."
It's now a little before 4 p.m., and the tornado paparazzi are standing by in another dusty town along the interstate, waiting for the storm to take shape. Among them is Daniel Shaw, who travels from Australia to the U.S. to chase storms.
"There's something about America and its storm systems that just produce these monsters," he says. "You just don't get things like this in Australia. I suppose it's strange — America's a long way to come to see a storm, but what you have here is truly incredible."
At 5:18, the caravan races toward to where the sky is darkest. Within minutes it's apparent the hoped-for EF2 isn't going to show: once-ominous clouds quickly break apart. The sun pokes through. No tornado today.