The arrival of spring can mean trouble for those of us living in Tornado Alley.
The term Tornado
Alley refers to the area east of the Rocky Mountains extending from Texas and
Oklahoma in the south up to the Dakotas in the north and eastward toward the Atlantic Ocean.
While tornadoes can occur almost anywhere, this particular part of the planet gets more than
its fair share of the things. We have our geography to thank for that. In spring and summer,
the middle part of the country often becomes a battleground when warm, humid air from the
Gulf of Mexico collides with colder, drier air from Canada. This collision spawns dramatic
thunderstorms, and if conditions are right, tornadoes.
There is still a lot that we don't know about tornado mechanics, but put simply, tornadoes form
when warm air meets cold air in a thunderstorm and starts to spin:
moist air is lighter than the cold dry air, making for a strong updraft within the thunderstorm.
As the warm moist air rises, it may meet varying wind directions at different altitudes. If
these varying winds are staggered in just the right manner with sufficient speed, they will act
on the upward rising air, spinning it like a top. The storm will begin to show visible rotation,
often forming a wall cloud. Inside
the storm these spinning winds can begin the formation of a tornado.
'I'll Get You, My Pretty'
Many people's closest encounter with a tornado is the movie 'The Wizard of Oz'. They're
lucky. Meteorologists classify tornadoes by their wind velocity or the amount of damage they
do. This is called The
Fujita Scale (or F-Scale) of Tornado Strength. The scale ranges from F0, with 40-72
mph (64-116 km/h) winds doing little damage, up through F5, packing winds of 261-318 mph
(419 to 512 km/h) and levelling everything in the storm's path. Tornadoes generally cause less
damage than a hurricane because they're a lot smaller and pass by quickly. But their violence
is concentrated and focused: the stronger ones can cause incredible amounts of damage, and
they can kill. Buildings explode. Motor vehicles are picked up and tossed aside like toys.
Livestock caught outdoors can be flayed alive.
Fortunately tornadoes occur infrequently. The 100,000 or so thunderstorms in the United
States each year spawn only about 1,100 tornadoes. Most of these occur in the spring in
Texas, Oklahoma, and Kansas and do little more than tear up wheat fields in sparsely populated
places. Only about 20 a year are 'killer tornadoes' like the powerful ones that roared through
Missouri, Kansas and Tennessee earlier this month, killing 40 people.
Around here we've learned to live with dramatic weather. Meteorologists watch for
dangerous conditions and broadcast alerts as needed, to the point of overdoing it. One day last
autumn a line of severe thunderstorms was approaching the area, and we were getting 'weather
bulletins' every five minutes or so. According to a friend of mine who works at a nearby hotel,
some tourists from Sweden were afraid to leave the hotel after watching the news. They
couldn't understand why the natives were going about their business as if nothing were wrong.
In fairness to the Swedes, the talking heads on TV were in full 'Armageddon mode' and the
skies did look as if the world were about to end, but that really is business as usual for those
of us who live here.
'And Your Little Dog, Too'
Still, there is no end to the craziness that humans will get up to. We're endlessly
fascinated with our weather, to the point where allegedly-sane people go out during storms and
try to catch a tornado in the making. These storm chasers come in two flavours: the
professionals (meteorologists, researchers at universities, and the like) and the amateurs. The
latter are people who are interested in meteorology and who want to see severe weather up
close or who want to film the storms. I'm one of them. When others head for the basement, I
get into the car. There is something awe-inspiring about Mother Nature doing her level best to
kill you. I suppose it's no different from any high risk activity; the human animal often feels
most alive when it is scared silly.
Those who enjoy being frightened in the company of like-minded individuals can sign up with
a travel agency that specializes in tornado chaser vacations. (Disclaimer: I do not work for
any of these companies, nor have I done business with them.) One enterprising Australian
company called Thunderbolt
Tours organizes trips to the United States during May and June and trips in
Australia during November through January. Others such as Tempest Tours Storm Chasing
Expeditions, Tornado Alley
Safari, and Storm Chasing Adventure
Tours concentrate on tours in the United States only. There are also a number of
Web sites devoted to storm chasing that allow people to contact each other and organize
The typical storm chase involves long periods of boredom interspersed with, if the chasers
are lucky, several minutes of terror. They generally drive 400-500 miles per day, returning
to their hotel rooms late at night to sort through their pictures, check weather predictions and
meteorological data, and plan the next day's chase. The weather sets the schedule, so chasers
eat and sleep irregularly or not at all and are exhausted a lot of the time. And the odds of
actually encountering a tornado are not good. Storm chasers need strong constitutions to
handle the long days, cast-iron bottoms to handle the long drives, and the patience to deal with
many hours of nothing much happening.
They'll tell you that life just doesn't get much better than this.
Not in Kansas Anymore
It's smart to stay indoors when tornadoes threaten, but you may be caught outdoors
anyway. You can find tips on How to Survive Extreme
Weather in The Hitchhiker's Guide. In general, remember:
- A tornado is often preceded by a few minutes of eerie calm. The skies can take on a
sickly green or yellow colour, and some people also have described an odd sulphur-like smell in
- A tornado really does sound like a freight train coming through.
- Tornadoes don't like to climb hills and often swerve to avoid one.
- If you see a tornado that doesn't appear to be moving, then it's coming straight at you.
Get out of its way. Now. Move at a right angle to the path of the tornado and find the nearest
sheltered or low-lying spot. Don't try to outrun it - you can't.
- If you're on the road, don't stay in your car - you and the car may end up in Oz. If at all
possible, get under a bridge or overpass. If none is available, get into a ditch or low-lying
area, crouch down as low as you can, and cover your head to protect it.
Want to chase storms and tornadoes from the safety of your computer? Here are some
Web sites with photos and videos of tornadoes in action:
Remember, don't panic!