Mark Stratton experiences the (literally) hair-raising thrills of twister-hunting in America's Midwest

Talking weather may be a British preoccupation but in Oklahoma I'm out of my depth. Two nights back in Woodward County we watched lightning like I have never witnessed before. Bolts lit up the sky like fireworks. The following day our car was pummelled by hail the size of dimes. Now, dark skies are gathering over the prairies promising the Holy Grail of storm chasing - tornadoes.

Over three days, my guide Stephen Levine and I have driven 1,000 miles along the interstates and backwaters of Oklahoma and the Texan panhandle looking for big storms. Life certainly isn't glamorous. We've slept at roadside motels and grabbed fast food drowned in have-a-nice-day platitudes at cheap Midwestern diners. And Levine's no Helen Hunt, the meteorologist with model looks in the 1996 movie Twister which was filmed around these parts. Wild-eyed and goateed he reminds me of Frank Zappa.

But Levine has a nose for big storms. He's been taking clients' storm chasing for the past eight years; converting a childhood obsession into a career. Levine is not a meteorologist but using a mixture of intuition, TV forecasts, and divine intervention - "I see God in all the storms and chasing them is a way of getting closer to the Creator"- all three days on the road we've run into storms which have left me shaking.

Levine turned up at my motel in Oklahoma City, attached an aerial to my Japanese rental-car, and away we went. I'd hired him, outside of his regular tours, for four days to be my personal guide. He's one of a growing number of storm-chasing outfits offering holidays to those in pursuit of extreme weather. Seeing spectacular storms during May is a certainty, but most guides will tell you the chances of seeing a twister during a week on the road is little better than 20 per cent. Tornadoes on average touch down for less than 10 seconds at a time, and the so-called "Tornado Alley" is a vast territory covering Oklahoma, Texas, Kansas, and all the way to Michigan.

Today, however, is looking promising. We're near a place called Hobart, and north-easterlies are blowing against local winds creating a freakish weather phenomenon known as wind-shear, a prerequisite for tornadoes.

By now Levine's short-wave CB radio crackles like popping corn. Weather reports from other chasers are flooding the airwaves. I find myself feeding off their gung-ho excitement; almost blasé to the potential dangers twisters can wreak. "It's like going on a tiger safari; you get near enough to take a photo but any closer and you get your head ripped off," says Levine. Some storm-chasers try to "punch" storms by driving through them but we position our car on a small hillock and wait patiently. There's electricity in the air. Rumbling thunder closes in and super-charged winds prickle the hairs on my arms. We can see a low, dark parcel of cloud heading close by. It's a supercell: a highly-pressurised thunderstorm.

"It's very unstable," Levine yells above a now- whining wind. Sure enough, the base of the cloud is rotating. So is my brain. What on earth am I watching? It is as if some clever special-effect has taken on a life of its own and busted out of a film studio. A green sheen forms around the storm as it drifts past, and then a trailing vortex tries to lower itself below the cloud base.

It never did touch down; instead we're treated to a 10-minute blitzkrieg of shifting lightning patterns and thunder. Then dead-still calm breaks out as sunset finally squeezes under the bruised clouds to flood the prairies with a gorgeous light. As we drive back to my motel I reflect how a touch of frost back home will never seem interesting again.

Stephen Levine (tel: 001 972 889 0196, runs week-long storm-chasing tours in May from $1,100 (£600) not including flights or accommodation. Storm Chasing Adventure Tours (tel: 001 303 888 8629, offers six-day tours from $1,900 (£1,000) without flights

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