What's a Tornado?

If you have a funnel cloud, a spinning vortex of air in the sky, and it touches the clouds at one end and the ground at the other end, you've got yourself a tornado.

The surprising thing about tornadoes is that it's mostly about the way hot and cold air react to each other. Wind in general is caused by hot and cold air. You might have seen a spinning movement at the top of your cup of coffee or tea as it reacts to the cooler air above it. This is heat and cold pushing each other around -- the basis for all changes in weather.

Thunderstorms create low enough pressure that there's essentially a vacuum beneath the clouds. Get these two phenomena going on at the same time, and you can get a column of swirling air. Let that spinning cloud touch the ground and you can get circling winds at 300 miles an hour. That's a lot of power.

While tornadoes are strong enough to pick things up -- the clock tower at William Jewell College in Liberty, Missouri got carried off to a neighboring town a few years back -- the main danger is in having things fall on you. A good strong roof can protect you. Get inside, get low, and make sure you're out of the way of windows.

The force of a tornado is such that it can rip a roof from a house, or even pick up part of a house and drop it somewhere else. A strong roof can't always protect you from every tornado. However, most injuries in tornadoes are from falling debris. Keep that in mind next time you hear a tornado warning. Take shelter in a cellar if you have one, and otherwise choose a central part of the building you're in and keep as protected as possible.

It's all part of living here in Tornado Alley.