What is a Tornado?



Have you ever really asked yourself, "What is a tornado?" Remember the mid-90's when "storm chaser" became the fad job to have? We have the 1996 motion picture "Twister" and The Weather Channel to thank for that. Before then, did we ever really have a fascination with chasing after tornadoes?

I can't imagine anything more frightening in terms of weather phenomenon than watching a tornado bear down upon you. Like earthquakes, tornadoes are unpredictable in terms of when they may appear. Fortunately, there can be a little bit of warning when a funnel cloud begins to develop. Technology today can at least predict when conditions are prime for a tornado outbreak. Radar can also spot the "hook echo" formed by the rotating winds of a potential tornado although this does not necessarily mean there is a tornado associated with it.

Tornado Formation

In order to answer, "what is a tornado," we need to know how they develop. Tornadoes form in large rotating thunderstorms called supercells. These storms occur where cold, polar air meets warm, tropical air. As wind comes into the storm, it causes an updraft and begins to swirl, eventually spinning faster and faster becoming a tornado. Tornadoes tend to rotate cyclonically. This means they rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Tornadoes can range in size from just 7 ft across to up to 2.5 miles across. They can also travel from a few miles per hour up to over 70 mph. In the United States, tornadoes tend to travel in a northeasterly direction.

Interestingly, the actual tornado itself is not visible. What we are seeing when we visualize a tornado is water vapor that has condensed within the high winds of the funnel. Also, as a funnel cloud touches the earth's surface, it will begin to pull up whatever type of terrain it passes over. Thus, a tornado may appear red when passing over a clay desert floor or blue if passing over water (in the form of a waterspout). Be sure to check out our tornado pictures.

Tornado Myths

There are many myths surrounding tornadoes. You may remember some growing up. Here are just a few we could recall:

  • Can you remember your parents running through the house and opening up the windows when a potential tornado may have been approaching? There once was the belief that opening all the windows of your home would allow the air pressure to balance if a tornado passed by, thereby reducing the chance that your house may "explode". Rest assured, the pressure change from a tornado is not the root cause of your house being torn apart. The destruction will be caused from the high winds. It is actually safer to keep your windows closed.
  • "Tornadoes don't hit the downtown areas of cities." Well, you can scratch that one too. Just ask the folks who lived in the Salt Lake City area back in 1999. Tornadoes can hit anywhere.
  • Another good one is the idea that you should park under a highway overpass if you are caught driving as a tornado appoaches. Most definitely not! In fact, overpasses may actually amplify the wind speed of a tornado as it pass through. Stay away from overpasses. Drive in the opposite direction of the tornado or get out of your car and into a ditch.

Hopefully, this has helped you answer the question, "what is a tornado?" As with any major weather phenomenon, get yourself prepared ahead of time. Be sure to review our tornado emergency preparedness plan, particularly if you live in an area with high tornadic activity.




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