DESTRUCTIVE TORNADOES

April, May and June are the peak months for tornadoes in the US. You have probably heard of the term "tornado alley" which refers to the continental plains and Gulf Coast of the US. More tornadoes strike this area than any other. The fact is, however, that tornadoes can strike anywhere. The average number per year in Pennsylvania is 31 which is higher than any other state on the east coast except for Florida. Given their phenomenal destruction, a little knowledge can go a long way towards saving your life.

Their lives are short, and so is the path they travel, yet few disasters can match a tornado. Within seconds of touching down, a tornado can leave a neighborhood little more than rubble.

A tornado is a violently rotating column of air. When the column of air does not touch the ground and does not produce damage, it is called a funnel cloud. As the tornado nears the ground it churns up dust and debris. Tornadoes vary in size, intensity and appearance.


Tornadoes are rated according to the damage which they can do on a scale called the Fujita scale. Most tornadoes are weak, with winds less than 100 mph (classed as F0 and F1.) About 1/3 of tornadoes are classified as strong, with winds around 200 mph (these are classed F2 and F3.) It is the F4 and F5 tornadoes which are truly deadly. 70 percent of all tornado deaths are caused by these rare, violent storms.

The color of a tornado varies depending on size, direction of sunlight and type of debris it is picking up. The shape of a tornado varies and may change during its life. In its later stages, tornadoes tend to become more squat and highly tilted, but this does NOT mean they have decreased in strength! In really huge tornadoes, the classic funnel shape may be missing altogether, and the storm might look more like a large cloud moving across the ground or a large rain shaft.


The exact mechanisms of tornadoes are not understood but in a very basic sense, they can be compared to an ice skater spinning. As the skater pulls their arms in, they spin even faster. In the same concept, all air masses have some degree of spin. As that air mass moves into the intense updrafts of a thunderstorm, the rate of spin increases. Under the right conditions, a tornado is born, but there are many questions yet to be answered.

When we mention windspeed of 200mph we are referring to the speed of the rotating winds inside the tornado. The actual tornado moves across the ground around 30mph but can range from stationary to 70mph. The path of the tornado can be anywhere from a few dozen feet to well over a mile!


May is the month when the most tornadoes occur and afternoons are their favorite time. This is because afternoons are the hottest times of the day and peak time for thunderstorms. About 40 percent of all tornadoes occur between 2 and 6pm. Nighttime tornadoes claim more lives because they cannot be seen and because most people are sleeping.

So what can you know about tornadoes which might save your life? Knowing something about tornadoes and using common sense can go a long way towards saving yourself. Here are six tips everyone should be aware of.

1 Hail is closely related to tornadoes! Large hail may precede a tornado, so the areas of a thunderstorm adjacent to areas of hail is a good candidate for a tornado to form. Seek appropriate shelter and remain in the shelter until well after the hail has stopped, about a half hour until the storm has moved away.

2 Opening a window in a house with the idea of reducing damage from tornadoes is a myth! Most building have sufficient ventilation to allow for the sudden drop in atmospheric pressure related to tornadoes. It is a myth that opening a window will allow inside air pressure to equalize with outside air pressure. Actually, opening the wrong window can increase damage.

3 Most deaths from tornadoes are caused by flying debris. Stay in the center of a building away from windows and exterior doors. Bathrooms and closets offer good protection if a basement is not available. Bathrooms have added support from pipes. Large rooms are more likely to have roof collapse.

4 Tornado wind speeds increases with height within the tornado. Storm cellars and well protected basements offer the best protection from tornadoes. In high rise buildings, occupants should try to reach the lowest floor and take shelter in small rooms or stairwells.

5 An approaching tornado may sound like a loud roar such as that from a freight train or airplane. At night or in heavy rains the only clue to a tornado may be the roar from its winds.

6 Although most tornadoes occur in the afternoon, they can occur at any time or the day or night.

The key to survival is awareness and planning. All members of the household should know where the safest areas of the house are. Make sure everyone knows that they may only have seconds of warning and that they must never hesitate or pause to grab toys or valuables. Perhaps the most important rule is Don't pause to gawk or get a video camera! While such videos might look dramatic, anyone with common sense will look at it and wonder how low on the IQ scale the camera person was!