h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I'm not sure about some of this.

Tornadoes are nearly always preceded by a good thunderstorm. The cumulo-nimbus clouds are generally a sign that a storm is brewing but the tornado doesn't form in them. Instead it arises from something called a 'wall cloud', which looks like a solid black wall lying across the sky.

Kansas is part of Tornado Alley, but I don't think it gets most of the tornadoes, 'Wizard of Oz' to the contrary. Oklahoma and parts of Texas seem to get the worst of it, although the 'hot spot' varies by year. And 29 tornadoes annually? We see more than that in an active month.

Experts also do not recommend trying to outrace a tornado. A car is the worst place you can be if you're caught in one. If there is no sturdy building handy, you should leave the car and get into a ditch or other low-lying spot, and cover your head as best you can.

Tornadoes are noisy. The ones I've been in have sounded like freight trains. Others have said that the noise is more high-pitched, kinda like a UFO landing...

A bit of shameless self-promotion - For more about tornadoes and links to pictures of wall clouds and such, see my article that appeared in a few months back: http://www.bbc.co.uk/dna/h2g2/brunel/A1050328

quizzical
(whose has experienced her share of tornadoes)

Well, according to the National Oceanic and Atmospheric Administration (NOAA), http://www.noaa.gov/tornadoes.html, there are about 1000 tornados a year in the US. And whatever you do, you don’t want to hide under a highway overpass in case of a tornado. You will likely be blown out. There’s more about that video you might have seen where some people managed to survive under an overpass here: http://www.srh.noaa.gov/oun/papers/overpass/slide01.html