My version of

Tornado Myths


Chuck Doswell

Posted:  14 January 2013  Updated:  whenever

This is in response to questions I'm asked frequently, so I'm providing a summary here.  As usual, this is purely my own opinion and represents nothing that has been formally reviewed/vetted by anyone.  Comments are welcome if you're willing to have them posted here, along with my responses.  Send me an email to cdoswell & (click on the email link or cut and paste, replacing _&_ with @) with your comment(s).

1.  To reduce damage from the tornado, open windows to relieve the internal pressure.

This is complete nonsense, based on the erroneous notion that buildings explode owing to the rapid pressure drop associated with the passage of a tornado vortex.  It has been shown that for any typical home, there are enough air leaks to equalize the pressure, and the pressure forces are not likely to be strong enough to have such an effect, anyway.  Buildings are destroyed by the wind, not the pressure drop.  Opening the windows is a waste of time, as the tornado likely will do that for you, but in doing so, you're exposed to the danger of flying glass from the window if it breaks.

2.  Tornadoes have a funnel cloud all the way to the ground.

A tornado is the wind, not the cloud.  Some tornadoes have no funnel clouds at all, much less one reaching the surface.  See here for more details

3. If the funnel cloud dissipates, this indicates that the tornado is "going back up into the clouds".

This is simply false - to repeat, the tornado is the wind, not the cloud.  Changes to the funnel cloud aren't necessarily very significant.  If debris is still being churned up at the ground, the tornado is still going and still dangerous.  Tornadoes don't "go back up in the clouds" anyway - they dissipate.

4.  My location is protected from tornadoes by the river/a mountain/an Indian myth/or whatever.

Tornadoes, especially strong-to-violent ones are tens of thousands of feet tall - they extend upward far into the cloud.  Minor topographic variations are unlikely to divert such a tornado.  Topography may influence whether or not a tornado is likely to occur in some locations, but isn't going to do much to divert a tornado should one develop.  Tornadoes have gone both up and down steep terrain slopes, and have occurred high in the mountains. 

5.  Never try to outrun a tornado in a motor vehicle.

This is a case of situation awareness.  If you're in a metropolitan area with lots of traffic and intersections with stop signs/traffic signals, it's not prudent to try to escape an approaching tornado in your vehicle, unless it's a long ways off.  But on rural roads, it generally takes only a very few minutes to drive out of a tornado's path, if you move at right angles to its forward motion - if it's approaching from the west, then go either north or south to escape it (south is probably better in the Northern Hemisphere).  If you're on an Interstate with limited access and the tornado happens to be moving in the same direction as you, then you can usually outrun almost all tornadoes at interstate highway speeds (70 mph), until you can reach an exit where you can drive out of the path. Your first goal if you see a tornado while you're in a motor vehicle is to determine which way it's moving!  Then you have to make a decision about your chances of outrunning it.  If you have any doubts, then abandon your vehicle and seek the best shelter you can find.

6.  The tornado is coming right at me!!

I've frequently heard such a statement from excited people as they're shooting video of a tornado, when it's obvious to me that the tornado is not coming right at them.  I don't understand why people can see what I'm seeing and draw such a diametrically opposed conclusion.  If it's moving past foreground objects to the left or right, it's not coming right at you.  On the other hand, if it seems to be standing still, but growing larger, then it is coming right at you.

7.  Tornadoes never hit big cities, so I'm protected.

This one is simply false.  Big cities can be and have been hit.

8.  Tornadoes just don't happen here.

Unless you live in Antarctica, this is another statment that's just wrong.  Tornadoes have been observed on every contintent and in every American state at every hour of the day and in every month of the year.  A relatively low frequency is not the same as a zero frequency.  This comforthing myth can kill you!  Furthermore, if a tornado can happen, I know of no scientific reason to believe that only weak tornadoes will occur, as some people seem to believe. 

9.  Tornadoes often strike without warning.

This is generally false, especially for strong or violent tornadoes.  Generally, if you didn't hear a warning, it's probably your fault, not because one wasn't issued.  Of course, this is sometimes true, but much less often than people think.

10.   A tornado sounds like a freight train.

I don't know why people say this.  I've heard tornadoes several times, and to me they sound more like a waterfall than a freight train.  I suppose a freight train includes a constant loud rumbling noise, but I don't believe that tornadoes sound anything like that.  Certainly no "hooooonk-hooooonk" and no "clickety-clack"!

11.  Tornadoes move erratically and randomly, which makes them difficult to evade.

For the most part, a tornado moves in the same general direction and at about the same speed as the thunderstorm that produces the tornado.  They don't generally change speed and direction very rapidly, except for minor "wiggles" along the track.  Only when the "parent" thunderstorm is moving very slowly can the tornado path be complicated. 

12.  Tornadoes are irresistible forces that always flatten anything in their path, so trying to build a tornado-resistant home is useless.

Most tornadoes are weak and there are many construction enhancements you can use to make your home more resistant to a tornado.  Even in a tornado that is rated "violent" (which is capable of flattening most homes), most (more than 90%) of the damage path is characterized by damage that is less than violent, for which structural measures will provide meaningful resistance.  Only an unlucky few are struck by the violent winds in a violent tornado.  See here for more discussion.

13.  My personal safety in the event of a tornado is the government's responsibility.

Although the government-issued warnings for tornadoes have saved many thousands of lives over the years, your personal safety is always in your own hands.  If you do nothing to protect yourself and your loved ones without having to be told what to do, when to do it, and how to do it, then you're much more likely to have a bad outcome, should you be unlucky enough to be in the path of a tornado.

14.  We're OK because have a plan for what to do when a tornado threatens us in my home, my school, and my workplace.

Even if you've prepared enough to have a plan in all three locationsm, that's good!  However, my experience suggests that many such plans are seriously flawed and might not offer anything like adequate safety.  Have someone who knows what it takes to develop a proper plan review your plan and make suggestions, if needed.  It's not enough to have a plan only at home, although it's distinctly better than no plan at all.  You also need a plan for what to do when traveling.

15.  Go to the southwest corner of your basement in a tornado.

If you have a basement, the best thing to do is hide under a stairwell or a sturdy table/workbench in case debris falls into the basement.  The notion of the southwest corner being the safe place is not necessarily valid.

16.  You can tell how strong a tornado is just by looking at it.

Although large tornadoes often are strong or violent, this isn't always the case.  The fact is that a tornado's appearance is an unreliable indicator of its intensity.  And the wind speeds can change rapidly, so the best practice is to assume any tornado you see is potentially life-threatening and take action appropriately.

17.  Mobile homes attract tornadoes.

The reason we hear so often about mobile home fatalities is that they're typically quite flimsy when compared to a regular, well-constructed frame home.  So even if a tornado just brushes a mobile home location, its weak construction increases the vulnerability of its residents by about 10-20 times more than in a quality frame home.  Currently, about 50% of tornado fatalities occur in mobile homes, on the average.  If you live in a mobile home, you definitely should not seek shelter there, but rather have some adequate alternative sheltering location already selected.

18.  Tornadoes only happen during the spring.

This is another one that's just not true at all.  Tornadoes have been observed in every month of the year, as noted above.

19.  Global warming means tornado frequency and/or intensity are going to increase.

At this time, there's no compelling scientific evidence that this is the case.  It might be true, but we have no way of knowing that with any certainty right now.  This may change as a result of scientific research, but at this time, it's just not possible to be sure.

20.  A highway overpass can be used to provide a tornado shelter.

See here for a more complete discussion.  The fact is that a highway overpass offers little or no protection from a tornado, so don't use them for shelters!

21.  All tornadoes are the same.

In addition to coming in different intensities, there are at least three very different types of vortices:  those associated with the mesocyclone of a supercell, those not associated with a mesocyclone, and the so-called "gustnadoes" which are not really tornadoes at all.  Waterspouts are tornadoes, by the way!  See here for an extended discussion.

22.  If you're not below ground when a tornado hits, you'll die.

This is a media-created myth.  Being in a tornado-resistant shelter, including those underground, is the best possible shelter if it's available, of course.  Anything less, and you're more or less dependent on luck for survival.  However, in most cases, most people sheltering above ground in an appropriate location (within a frame home, for instance) likely will survive unless the building is completely swept away. 

By going to this webpage, access to many essays by me about tornadoes (and other topics) can be found.