Weather Imagery

Tornadoes don’t really hop, jump or skip. They can pull back up into the clouds and come back down sometime later, but this usually occurs over a fairly large distance. On a smaller scale, people tend to believe tornadoes can hop or jump over one house while totally destroying the one next to it. While this is true that a tornado can completely destroy one house and minimally damage another right next to it, the real reason has nothing to do with a tornado jumping or skipping. It has to do with the internal structure and varying intensity of a tornado.

The funnel of a tornado is sometimes composed of two or more vortexes which are just like smaller tornadoes that spin around in a circle (as seen in the picture to the left). This kind of tornado is called a multiple-vortex tornado and is almost always responsible for narrow paths of extreme destruction. We normally can’t see the individual vortexes because condensation and debris obscure the internal structure and give a tornado that wedge shape appearance.

Even though a tornado can be a hundred yards or greater in width, these smaller vortexes may only be a couple dozen feet in diameter and follow one another, often referred to as “training”. The winds in the vortexes can easily spin in excess of 200 mph and are actually responsible for a majority of a tornado’s destruction. Since these vortexes are only a couple dozen feet across, they represent a smaller portion of the entire tornado funnel. So as the tornado moves into a neighborhood, almost all the houses will suffer some damage from flying debris and the surrounding winds, but those that get hit by a vortexes will suffer far greater damage compared to those which didn’t. That means one house may be totally destroyed while the house across the street may still be standing and have considerably less damage. This is the main reason why it looks like tornadoes skip over one house while completely destroying the one right next to it.

On a slightly larger scale, a tornado can destroy one neighborhood while only lightly damaging the next in its path of destruction. A tornado’s destruction can vary significantly in just a quarter mile or so. As an example, one neighborhood might experience destruction consistent with an F3 tornado, but by the time the tornado crosses into the next neighborhood, the intensity might have dropped off considerably down to an F1. By the time it reaches the next neighborhood, it could very well have re-intensified into an F3 or greater. The neighborhood lucky enough to experience F1 strength destruction will suffer far less damage compared the to other areas that experienced the F3 or greater tornado intensity. This may give the appearance that the tornado skipped over a set of houses in one neighborhood while destroying everything else in front and behind it.

Because of the above reasons, damage reports vary for the same tornado event which make classifying the tornado on the Fujita Scale (the F-Scale) difficult. A new enhanced F-Scale will be implemented starting February 1st, 2007 to address this problem and make tornado reporting more accurate.

Other Tornado Myths

• Do Mobile Home Attract Tornadoes?
• Does Opening Windows During a Tornado Help?
• Is The Southwest Corner Safest?
• Do Highway Overpasses Provide Safety?
• Can You Really Outrun A Tornado In A Car?