05/21/2013 06:57 pm ET Updated Dec 06, 2017

What Is A Tornado? How Tornadoes Form Explained By NOAA Scientists

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The deadly Moore, Okla., tornado has people asking: Just what is a tornado? And how do these dangerous storms form?

The National Oceanographic and Atmospheric Administration (NOAA) website notes that a tornado is a narrow and violently rotating column of air that extends from the base of a thunderstorm to the ground.

A storm brews when warm, moist air rises and mixes with cold air. Then if winds change their speed and start to rotate, causing a high-level rotating storm (called a mesocyclone), a tornado may eventually touch down.

tornado formation

But as to which specific combination of these these weather factors causes a tornado, no one really knows. In fact, predicting when a tornado may form is so complicated, the U.S. Weather Bureau discouraged issuing tornado forecasts until 1950.

In the U.S., about 1,200 tornadoes hit each year -- and some researchers have pointed to the nation's midsection, known as "Tornado Alley," as most likely to harbor tornado-producing weather patterns. In addition to Oklahoma, this area includes eastern South Dakota, Nebraska, Kansas, northern Texas, and eastern Colorado.

For more tornado science, check out these seven dangerous misconceptions.



May Tornadoes 2013