With summer underway, there’s something more dangerous in the air than sunburns and bee stings—tornados. While I’ve always associated tornados with Wizard-of-Oz whimsy, the word “tornado” has a different ring for many Americans, invoking horror instead of whimsy. As devastating as tornados can be, they are also fascinating meteorological events—that is, when observed from a distance.
What’s Up with the Weather?
Tornados are vortices of wind that occur in or below a cloud and occasionally touch ground. Since tornados are simply air, they would be invisible if not for the dust (and occasionally the cars, cows, and houses) they kick up. We normally imagine tornados as a single vortex of dust (these are officially titled “dust-tube tornados”), but tornados have several meteorologically-recognized forms, including “waterspouts,” which occur above large lakes or oceans and suck up tubes of water instead of dry debris.
Meteorologists measure tornado severity using the Fujita scale (after Ted Fujita, who designed the scale with Allen Pearson in 1971). The Fujita scale assigns tornados a grade between F1 (“moderate tornado”) and F6 (“inconceivable tornado”) based on wind speed and damage.
- With wind speeds ranging from 73 to 112 mph, an F1 tornado can peel the roofs off houses and overturn cars and mobile homes.
- An F2, or “significant tornado,” involves winds from 113 to 157 mph, causing considerable damage, demolishing mobile homes, and uprooting trees.
- An F3 is a “severe tornado.” Its 158 to 206 mph winds would tear the roofs and walls from even well-constructed houses, overturn trains, and uproot entire forests.
- An F4, or “devastating tornado,” is seriously bad news. With 207 to 260 mph winds, an F4 tornado would level houses, blow large buildings around, and create “large missiles” of flying cars and other objects.
- An F5, or “incredible tornado,” is the most extreme recorded level of tornado. An F5 involves wind speeds of 231 to 318 mph and would lift houses (and carry them significant distances), debark trees, toss vehicles, and damage even steel-reinforced concrete buildings.
- The mythological F6 tornado, which would occur with wind speeds over 319 mph, is highly unlikely. The damage by F6 winds would be hardly relevant amidst surrounding F4 and F5 damage. Engineering studies would not necessarily be able to document this tornado. Rather, they might classify it as a family of F4 and F5 tornados.
The Worst of the Worst
The Great Plains, known as America’s “wind corridor,” provide the seasonal storms that stir up serious tornados. This explains why a large percent of tornados worldwide occur in the Oklahoma/Kansas area.
Experiencing 1,000 tornados every year—42 percent of them meriting a score of F2–F5 on the Fujita scale—the states are a hotspot for these killers, some of which remain painfully clear in the national memory. A few noteworthy tornados within the last century include:
The Tri-State Tornado (F5)
This twisted sister swept through Missouri, Illinois, and Indiana in 1925. Recognized as the most devastating tornado in U.S. history, the Tri-State killed 625 people, injured another 2,000, and caused almost seventeen million dollars in property damage (that was a big deal in 1925).
The Tupelo and Gainesville Tornados (F5 and F4, respectively)
The year of 1936 was somber in terms of tornados, scarred by not one, but two, serious twisters. Combined, the Tupelo Tornado (Mississippi) and the Gainesville Tornado (Georgia), both which occurred within the same storm system, resulted in 436 deaths and destroyed hundreds of residencies and major buildings.
The Woodward Tornado (F5)
This nasty 1947 tornado (more accurately, a family of tornados) was more than two miles wide and spanned nine counties. The family of tornados killed over 180 people, injured nearly 1,000, and destroyed hundreds of city blocks in Woodward County alone.
The Flint and Waco Tornados (F5)
The year of 1953 marked another historical onslaught of tornados; combined, the Waco Tornado (in May) and the Flint Tornado (in June) killed 129. The Waco Tornado alone damaged 600 businesses, 850 homes, and 2,000 cars.
The early- to mid-twentieth-century may have monopolized U.S. tornado history, but some tragic twisters have made appearances in recent years as well. Dozens of killer tornados swept the States in 2008 alone, most notably an F5 in May that killed seven people, hospitalized fifty, and destroyed the Southern and Eastern sections of Parkersburg, Iowa. So far, there have been no F5 storms during 2009.
Stay Safe During the Storm
Tornados remain a constant threat in the Great Plains area, so it’s wise to stay up-to-date on tornado safety procedures. Oklahoma’s Storm Prediction Center (SPC) describes the most common tornado warning signs as strong cloud base rotations; whirling dust near the ground (some tornados don’t stem from obvious funnel clouds); thunderstorms, hail, or heavy rain; and, at night, bright flashes near the ground that indicate power lines being snapped by strong winds that could cause tornados.
The SPC recommends retreating to a basement (if there is one) and covering yourself with a mattress or sleeping bag. If you know the locations of heavy items like pianos or waterbeds on the floors above you, avoid lying directly below them—they might crash through weakened floors.
If your residence doesn’t have a basement, the SPC suggests hiding in a small, central area of your building (like a bathroom or stairwell), making sure to keep away from windows and other glass and covering yourself with any available thick padding (mattresses or sleeping bags if you have them; heavy coats or blankets if you don’t). Stay out of elevators. If you’re in a mobile home/vehicle, GET OUT—vehicles may fly even in F1 tornados. If you’re driving and can see the tornado far away, you might be able to drive out of harm’s way. However, if the tornado disappears from view or seems to be drawing nearer, you should abandon your vehicle immediately. Seek shelter in a sturdy building or, if you’re on the open road, on low ground as far as possible from cars/trees. Lie on your stomach, face-down; avoid hiding under bridges, which could crumble and bury you.
Most at-risk cities will broadcast tornado warnings over all television stations. If you live in a tornado zone and don’t have a television, or won’t be watching it frequently during tornado season, consider asking a friend or relative to call you and alert you in case of a broadcast.
Tornados are one of Mother Nature’s ways of reminding us who’s in charge. Although we can’t thwart a tornado’s force, we do have history to remind us that taking the right safety precautions can make the damage from an F5 seem a little more like an F4. We hope.