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GUYMON, Okla. — Oh, what a beautiful evening it is in the Oklahoma Panhandle. The sunset blazes orange, cattle graze on yucca flowers, and prairie grasses wave serenely toward the horizon.

At least, on one side of Highway 412.

On the other, a massive Supercell rotates low over the land. Black and purple, with a bright green heart of softball-sized hail, the circular thunderstorm uncannily resembles a spaceship in the movie "Independence Day." Vans, Doppler radar trucks, and emergency vehicles zoom along its periphery like ants rimming a giant carousel.

On the storm’s underbelly, ragged clouds start twisting into a drill-bit shape. Over the CB radio, on "chaser channel" 146.520 megahertz, meteorologist Bob Conzemius tells four vans of hopeful listeners, "It’s reorganizing."

Sure enough, the drill bit elongates into a crooked finger pointing toward the ground. All along 412 breath is collectively held. If that snaky green funnel touches down, it will become the most feared and destructive weather phenomenon in the Great Plains.

A tornado is precisely what the clients of Tempest Tours, an Arlington, Texas-based storm chase company, have traveled five days and almost 3,000 miles to see.

The "Glossary of Meteorology" (published by the American Meteorological Society) defines a tornado as "a violently rotating column of air ... pendant from cloud to ground." The weakest twister boasts 85-mile-per-hour winds; the strongest is a plus-250-mile-per-hour blender that liquefies everything in its path — which is what happened in Greensburg, Kan., on May 5.

Who would willingly seek out these vicious vortices? As Helen Hunt said in the 1996 movie "Twister," "Who are these people?"

First you have your specialists: There are approximately 200 professional storm chasers in the United States and five of them led Tempest’s Memorial Day tour this year. In the off-season, the Tempest specialists hail from Pennsylvania to California and range from a cabinet salesman to a wind specialist. Kinney Adams is a Wisconsin videographer, Keith Brown has a bachelor’s degree in meteorology, and tour director and seven-year Tempest veteran Bill Reid has a master’s in geography and is a climatologist. What do these men share? In most cases, a meteorology degree, and in all, an extreme love of extreme weather. Every storm season, from May to July, they’re cruising the Plains, guiding one of Tempest’s tours or chasing solo during downtime.

Then there are Tempest Tours’ clients, civilians willing to pay $1,895 to $2,550 per tornado safari. Most tours average six to 11 guests; there are 19 on this excursion, Tempest’s largest group ever. Not surprisingly, most of us converging on Oklahoma City’s Wingate Inn for orientation are "weather weenies." I’ve been tornado-obsessed since childhood when I saw a twister in my grandmother’s farm town. Marcia Perez, the tour photographer, shoots severe storms in her native Dallas. Leisa Luis-Grill, a nurse researcher and artist in Rochester, Minn., and a "Wizard of Oz" fanatic, requested the trip for her 50th birthday.

West Virginian Doug Nichols is a spotter for SKYWARN, a partnership between the National Weather Service and local emergency managers.

But eight guests come from storm-starved Britain and the Netherlands. How did they get hooked? "A Discovery Channel documentary on freak weather," says Peter Playford, a sixtysomething Londoner.

"I’ve been waiting 10 years, since ‘Twister,"’ says James Connor of Manchester, England.

"I have no interest in any of this," says his aunt Melanie Connor. "I stupidly promised I’d take James for his 18th birthday."

Californian Stacy Williams wins for most creative motivation: "I just like riding in vans with strangers."

Lucky for Williams, because as Reid explains, tornadoes are elusive beasts, and hunting them is more like chess than chasing. He projects the National Weather Service’s Storm Prediction Center website on the wall to highlight the necessary ingredients for "tornadogenesis": warm and cold air colliding, moisture, wind shear to induce rotation — and an unknown factor not even top scientists understand. One Supercell may spawn a twister while another, containing all the same elements, might not. Of about 1,200 tornadoes that touch down annually in the United States, most occur over rural areas and last about 30 seconds. And this can happen anywhere from Texas to North Dakota, in what is called colloquially Tornado Alley.

Essentially we’re embarking on an expensive gamble. Martin Lisius, president of Tempest Tours, says clients typically see tornadoes on five out of every six tours and they almost always see Supercells. But our tour could travel 500 miles a day to intercept a promising storm — with no guarantees, Tempest emphasizes.

"Storm chasing involves a lot of patience, a lot of waiting, and long hours of driving," says guide Brian Morganti. In other words, a lot of riding in vans with strangers.

Since we’ve already signed waivers absolving Tempest in case of any tornado-related deaths, our leaders brief us on noncyclonic dangers: rattlesnakes, lightning, too much liquid intake. Then we pile into four radar-laden minivans and hit the road. Destination: Hays, Kan., halfway to tomorrow’s hunting grounds in Nebraska.

We drive, grab beef jerky and Mountain Dew at truck stops, do a 19-person conga through restrooms, then drive some more. Entertainment consists of roadside kitsch — "See The World’s Biggest Prairie Dog!" — and our guides comparing storm stories. "Weren’t you here in 2001?"Reid asks over the chaser channel as we flash through Hoisington, Kan.

"April 21, F4 tornado," confirms Conzemius.

The next afternoon, near Ogallala, Neb., we spot our first Supercell. It hangs over the highway like a giant white anvil, its top sheared characteristically flat by strong stratospheric winds.

"Anyone see a ‘wheel of fortune?’ " Brown asks, referring to the spinning disk that appears on Baron Threat Net radar when a storm starts rotating.

Before anyone answers, we crest a ridge and see a translucent column connecting a tiny pointy funnel to a debris cloud. From our distance, it’s the size of a toothpick. We speed into a dip, and when we emerge, it’s gone.

"That was a tornado!" Perez and I scream.

"That wasn’t a tornado, folks," says Conzemius. "That was a landspout." A landspout, he explains, forms when dust gets sucked up by a storm’s powerful updraft winds, whereas a tornado originates from a wheel of fortune Supercell.

Our caravan has strong powers of denial. "I think that was a tornado," says Luis-Grill, aiming her camcorder toward the storm as it churns over a farm road.

"We could just pretend that’s a tornado," New Yorker Erik Trinidad suggests of the wedge-shaped rain core."Nobody at home will know the difference."

We stand shivering in the storm’s cold outflow winds, gaping skyward. A fleet of Supercells silently surrounds us on the horizon. But the show’s over for now, and the most exciting moment en route to Kadoka, S.D., is when we run over a rattlesnake.

For three days we are teased by storms. Near Limon, Colo., we chase what Conzemius calls "the icemaker," a huge, dignified Supercell that glows the astonishing deep blue-green of an Alaskan glacier and bombards us with golf ball-size hail.

In lonesome ranchland, we encounter what Brown dubs "the mustache storm of doom" because of two horizontal clouds kissing beneath its base. Over Capulin, a defunct New Mexico volcano, a Supercell inflates and collapses at time-lapse speed, taunting us with a rainbow as it disappears.

We drive through flooding downpours, a dust storm, a grass fire set by cloud-to-ground lightning, cattle herds, and a tumbleweed attack. As Dan Irwin, a British geologist, says: "Everything but the Big T."

Are the tornado tourists disappointed?

"No, because we’re seeing the America you never see," says Playford in the Badlands.

"It’s awesome," Nichols agrees, exploring a Colorado ghost town populated by cow skulls, rusting baby buggies, and a boxcar full of meat hooks. "Very relaxing."

And the occupants of van 3, the "Kitschmobile," are in heaven. As we pinball from Pierre, S.D., to Tucumcari, N.M., we discover Orange Crush cake, Frito Pie, supermarket skull rings, and the 80-foot Apatosaurus (formerly called a Brontosaurus) outside Wall Drug off Interstate 90 near the Badlands.

"This tour is like a trip through your childhood foods," says Luis-Grill, eating her favorite, Cherry Mash. "I’m having a wonderful time."

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On Memorial Day our 3,000-mile effort finally results in a closer encounter. We’ve followed this Supercell for six hours, observing its life cycle from cumulus puff to the monster mesocyclone now covering Cimarron County, Oklahoma. Around dinnertime, as we parallel the storm on 412, it produces a big anteater-snout funnel that quickly feathers apart.

But the storm isn’t done yet. Ten minutes later, Reid allows a short observational stop, and we join the "chaser jam" lining 412 just as Guymon’s sirens go off. The wind punches our vehicles and keens in the telephone wires. The Supercell’s base lowers further, extinguishing all light but a wink of sunset and its own luminous green core.

I’m thinking how much my grandmother feared that eerie phosphorescence when a thin funnel snakes from it sideways. It lengthens, crooks toward the ground, and touches down — for a few seconds. Then it retracts and is gone.

Our crew stands in silent awe. Or is it anticlimax?

I ask my van-mates during our post-midnight post-mortem in an Amarillo, Texas, McDonald’s.

"I’m ready to do it again tomorrow," says Nichols.

"Me too," says Connor, reluctant chaperone turned addict. "It was so beautiful I forgot to be scared."

There’s enthusiastic agreement. Everyone’s walleyed with adrenaline, talking like newly inducted cult members.

"I’ve never been a religious person," says Luis-Grill as we head out to get some sleep before our final day’s chase. "But that storm was like Communion — being one with something so much bigger than yourself."

~ Jenna Blum