Tornado Warning Signs

Tornadoes are destructive forces of nature that can strike with little warning and that can devastate homes, businesses, and anything else in their path. A tornado is a funnel-shaped whirling vortex of rotating winds appearing beneath a large storm system, touching the ground. Most of the time, tornadoes develop from thunderstorms, specifically when warm air from the Gulf of Mexico meets with cool air from Canada in the United States. According to the National Oceanic and Atmospheric Association (NOAA), tornadoes cause an average of 70 fatalities and 1,500 injuries annually.

The geography of the United States makes it a breeding ground for dangerous cyclones. The central states from the Gulf of Mexico up through Southern Canada comprise an area called “Tornado Alley,” where the Rocky Mountains block moisture, forcing drier air into the troposphere. “Tornado Alley” consists of Louisiana, Texas, Oklahoma, Nebraska, Kansas, North and South Dakota, Missouri, Iowa, and Arkansas. The United States averages over 1,000 tornadoes per year, so it is important to recognize the warning signs of an oncoming twister before it is too late.

Tornadoes are measured by the Fujita Scale, or F-Scale. Developed in 1971 by T. Theodore Fujita of the University of Chicago, the F-Scale measures the intensity of tornadoes by the amount of damage done by the cyclone passing over an area. An F-0 tornado, the weakest level in the F-Scale, will contain winds less than 72 mph and will generally cause light damage, breaking tree limbs and knocking over small, weak trees. An F-5 tornado, the highest level, will have sustained wind speeds of 261-318 mph, and will cause total, catastrophic damage, destroying almost every structure in its path and will lift up large objects like cars and trucks and send them flying like missiles through the air.

There are several warning signs for impending cyclones. Know them and you will be able to better protect yourself and your family in the event of an oncoming twister. It is also a good idea to have a tornado survival kit on hand, especially if you live in an area prone to twisters.

The most apparent way to know if a tornado is imminent is to take a look at the sky. If you see dark, heavy thunderstorm clouds with lower, swirling clouds taking a funnel shape, there is likely a tornado forming or approaching. Trust your eyes and common sense. If a funnel cloud is making its way towards you, whether it’s touching the ground or not, take cover as quickly as possible.

Another sign you’ll see by looking up is the color of the sky. Often before a tornado the sky will get extremely dark, commonly taking on a greenish hue. If you see the sky turning dark green, take cover immediately. Do not wait for a visible funnel cloud, as occasionally there will not be a visible funnel but a tornado may still be about to strike.

Rotating or whirling dust or debris is another sign a tornado is about to strike. Sometimes you cannot see the funnel, but a tornado may still be present. You may either see dust or debris blowing around on the ground or an approaching cloud of dust and debris.

Have you ever heard the term “the calm before the storm?” Well, tornadoes are often preceded by heavy rain or hail with or without rain present followed by either a dead calm or quick, noticeable change in the direction of the wind. Tornadoes are often concealed by heavy rains and cannot be seen. If you notice a severe change in weather or a drastic shift in the wind, it is imperative that you take cover as quickly as possible.

Your ears will also inform you of an approaching tornado. A loud, deep rumbling or roaring that sounds like thunder aside from the fact that it doesn’t fade away is another sign of an impending twister. If you can hear the rumble of the tornado it is close enough to injure you or cause damage to your home or office. Do not wait for the sound to become louder or closer; take shelter immediately.

At night, it may be more difficult to see a tornado approaching. Small green, blue, or white bursts at or near ground level indicate power lines being snapped due to severe winds, and are a good sign of an approaching tornado. Also, if you see lightening striking low to the ground, silhouetting a funnel shape, that is another sign of an approaching tornado.

It is always good idea to keep a NOAA Weather Radio or other weather transmitter in your home or car, especially if you live in an area prone to tornadoes. Tornadoes can strike anywhere in the country, not just in “Tornado Alley,” so keep your eyes on the sky and your ear to a weather radio to protect yourself and your loved ones from the destructive forces of one of the most dangerous natural disasters on the planet.