Thrill-seekers in search of a holiday with a twist head for wet, wild weather.
Some people choose the strangest ways to spend their holidays. There's probably nothing wrong with packing a suitcase and heading to the flat, central Great Plains of the US, to states such as Texas, Kansas, Oklahoma and Nebraska, were it not for a meteorological phenomenon.
This is where the cold, dry, polar air that drifts south from Canada meets warm, moist, tropical air wandering northwards from the Gulf of Mexico.
At this time of year, the place where they meet creates conditions perfect for the formation of tornadoes and storms.
For people looking for a new form of adrenalin buzz and known as storm-chasers, tornadoes are a tourist attraction.
A whole industry has built up around it. Meteorologists are employed to scan weather patterns and check barometric pressure, with vehicles and expert guides on standby ready to hurtle around the countryside in search of tornadoes and thunderstorms when conditions look right.
Storm-chasers will cover hundreds of kilometres a day in search of wild weather and are at their happiest when the winds are howling, the rain lashing down - even hail with a bit of luck - and lightning flashing all around. Or watching tornadoes forming to wreak the type of havoc seen in the movie Twister.
One specialist operator describes storm-chasing thus: "We focus on the scientific, artistic and spiritual aspects of storm interception, and encourage clients to appreciate the beauty in all types of storms as well as the landscapes they interact with." Such experiences do not come cheaply. A typical 10-day expedition with an expert, a minibus and motel rooms costs about $US2500 ($A3300).