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Don Paul: Debunking myths about tornadoes

Western New York is not exactly tornado alley. Longtime residents know we are not immune to them, although the recent lack of activity may make it seem so to newcomers. In my first spring here on May 31, 1985, a mega-outbreak which included eastern Ohio, northwest Pennsylvania, southern Ontario and upstate New York produced 44 confirmed tornadoes resulting in 90 fatalities. A stiff, chilly Lake Erie breeze weakened highly destructive tornadic supercells as they crossed into Chautauqua County from Pennsylvania. None of those fatalities occurred here, and Western New York had just one confirmed tornado :

So far this year, the U.S. is on a near-record pace for tornadoes, with high numbers in the plains, Midwest, and parts of the south. It remains to be seen if we experience more severe weather in Western New York than recently as we get further along during the spring. It would be a good idea for the public to become aware of some persistent tornado myths, some of which may produce a false sense of security, while others create undue alarm.

Myth: The southwest corner of a basement is the safest location. This myth came about because many tornadoes move from southwest to northeast, but there is no evidence to support it. The safest location in a home or building is the lowest level, preferably windowless location, most inward from outside walls. If there is no basement, pipes in bathroom walls can supply additional structural rigidity. If there’s time, covering up in padded quilts may afford some protection from flying debris.

Myth: Opening windows can help equalize outside and inside pressure and reduce damage. Actually, the time taken to do this increases your risk of injury from an approaching tornado. In fact, it is the destructive force of the wind, not an explosion due to pressure differences, which causes the damage. This has been confirmed by many structural engineers in damage surveys.

Myth: If you’re on the road with an approaching tornado, seeking shelter in an underpass offers protection. That myth really grew from a spectacular video which went viral after a powerful tornado passed over an underpass on I-35 in Kansas. All in the video survived. They were fortunate. In an underpass, winds and the debris they carry actually accelerate because they are being squeezed through a narrow opening. This is similar to the acceleration in winds which occurs downtown around tall buildings which block the wind. The wind sweeping around those buildings actually blows faster due to that squeeze play, which in physics is called the Venturi effect.

Myth: You can outdrive tornadoes. If you don’t know the lay of the land and the orientation of the roads, you have a better chance of being hit by the tornado if the roads aren’t oriented for your escape. This has cost storms chasers their lives as well. Tornadoes don’t follow roads and can get to you a lot more quickly than you realize while you’re searching for an escape route. It is better to get out, seek a structural shelter, or at least to lie flat if a tornado is upon your vehicle if no structure is available.

Myth: Tornadoes generally only occur on flat land, and low elevations. They are less common in truly mountainous terrain, but the hills of the southern tier would hardly qualify to meet that definition. An EF-3 tornado occurred at 10,000 feet out west. Tornadoes are more common in the southern tier of Western New York than any other part of our region

Myth: Tornadoes don’t occur in cities. It is true the City of Buffalo has not suffered a direct hit. That is more due to Buffalo’s proximity to the stabilizing cool waters of Lake Erie for a large part of spring and the first half of summer. But tornadoes are not stopped by the structures of big cities. Miami has been hit, Oklahoma City has been hit, a large tornado tracked from Tuscaloosa to Birmingham in 2011. There are many other examples, but cities have been hit quite often. The seeming rarity is due to the small percentage of the nation’s landmass which is actually occupied by cities, as opposed to rural terrain.

Myth: Tornadoes don’t cross rivers. Yes, they do cross rivers, and this has happened hundreds of times.

Myth: Tornadoes are easy to see once they draw closer. Sometimes that is true, but it is all too often false. For one thing, your vision may be obstructed by trees and terrain. For another, tornadoes are often wrapped in heavy rain and hail, obscuring your vision of the actual tornado. Rain-wrapped tornadoes have caught many, including less experienced storm chasers, unawares. Of course, at night tornadoes can be exceedingly difficult to spot.

Myth: If your vision is not obscured by the factors above, and the lower portion of the tornado appears not to be reaching the ground the risk from impact is lessened. In reality, the base of the condensation funnel is dependent on what kind of surface it’s crossing for its appearance. If a tornado is moving over a large concrete tarmac, there is little debris to be sucked into the vortex to make it more visible near the ground. In this case, the roaring noise may be a better indicator than what you’re seeing. If a tornado is crossing a dirt field, the opposite is true. It will be dark and opaque.

Myth: Green clouds mean a tornado is forming or is nearby. Green clouds mean a towering shower or thunderstorm is nearby, and the density of the moisture is scattering the light in such a way that green becomes a dominant visible shading. Tornadoes generally are associated with thunderstorms, but the vast majority of thunderstorms do not contain tornadoes.

Myth: You can estimate the strength of a tornado by its size. While it’s safe to say a very large, wide tornado is not weak, not every wide tornado is an EF-4 or an EF-5. The latter are statistically rare. The wide appearance may be enhanced by a broad area of plowed land feeding more dirt into the vortex. The designation of where a tornado falls on the Enhanced Fujita scale is determined by a damage survey afterward, conducted mainly by trained National Weather Service meteorologists. That scale is imperfect, but it gives a more accurate assessment than just looking at a large tornado.

Incidentally, despite having worked a year in Wichita, I have never eyeballed a tornado. A cold air funnel? Yes. Waterspouts off the Outer Banks? Yes. But a tornado? Only on radar. And in my dreams and nightmares. Years ago at an American Meteorological Society conference, I was chatting with Allen Pearson, who was director of the National Severe Storms Forecast Center for 14 years, before it became the Storm Prediction Center. He never saw one either, except on radar.

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