Tornadoes

Tornadoes are some of the most complex weather events ever to happen in nature. Spinning at up to 300 mph (480 kph), the vortex develops in a cloud and extends all the way to the ground. Without that connection between the vortex and earth, it is not classified a tornado.

The process of weather events that must take place prior to a tornado occurrence is called tornadogenesis. Tornadogenesis is a process in which cold air collides with warm at such a rapid interval that it creates instability in the clouds. A shift in wind speed, direction, or height at the same time can cause a large cell storm to develop, swirling more and more rapidly.

The rotating air extends downward, picking up debris and dust as it mounts in speed until its funnel touches the ground where it can wreak havoc. Inside the tornado, the air is lower in pressure, colder. It expands and moisture forms as a result.

There are many different kinds of tornadoes, varying in vortex shape and size. Some include rope tornadoes, named for their narrow funnel; wedge tornadoes, a wide base extending off a large portion of cloud cover; cone tornadoes, a conical funnel, wider at the top, and the most common image associated with tornadoes; and many more. They can change color based on the surrounding debris that is swirled into the tornado’s vortex. Colors range from white to brown, red, and even black.

Most tornadoes across the world happen on the Great Plains of the U.S., in an area known as tornado alley. There, large storm cells are the result of the combination of warm moist air coming from the Gulf and cold air blowing off the Rockies. About 30% of large cell storms produce tornadoes.

Tornadoes can be violent weather events. A tornado’s severity is measured using the Fujita scale, ranging from F-0, being the mildest, to F-5 as the most dangerous. An F-0 tornado might break off tree branches or overturn umbrellas; an F-5 can lift a car clear from the asphalt, spinning it up to 330 ft (100m) through the air.