How Do Tornadoes Form?

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By By Steve Pool

SEATTLE - Tornadoes are very complex systems and thus are difficult to forecast. First, you need a strong thunderstorm and warm, moist air near the ground. Strong thunderstorms will have strong upward moving winds as the warm air races upward, and downward moving winds from the heavy rain and hail falling.

These wildly varying winds will cause winds to be flowing from different directions near the ground. The colliding winds will cause a spinning horizontal tube of air along the ground. This tube will then get picked up by an updraft and brought into the thunderstorm, now making the cone of spinning air vertical. It's this spinning combined with strong updrafts that make a tornado, and why tornadoes work like a vacuum -- they're pulling air upward.

For More Information:

www.nssl.noaa.gov

Your Photos

YouNews House destroyed by tree House destroyed by tree
Cottonwood tree felled by today's windstorm destroyed home in Lynnwood. Occupants - fearing the intensity of storm - retreated safely to their basement just minutes before the tree fell. House is a total loss.
YouNews Wild winds turns into 3 totaled cars Wild winds turns into 3 totaled cars
A huge tree, in Lynwood, snapped in half causing branches to brake windshields open, damged equipment, and frontal damge of a car. Started out as simply winds, leading into wilder then moments before causing a rather large tree to fall over and hit three cars.
YouNews Changes on the way Changes on the way
The cloud bands around Mt. Rainier are a sure sign of changing weather conditions. These images of Mt. Rainier were taken Thursday evening around 7:30pm with a Nikon D3000
and a 200mm telephoto lens. The dark spots on the 1st image is flock of birds (not dirt on the lens).