Atmosphere And Weather

Tornado Formation Tornadoes Explained Tornadoes Destruction Twisters Cyclones Funnel Clouds

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"Tornado Formation Tornadoes Explained Tornadoes Destruction Twisters Cyclones Funnel Clouds"
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Can you imagine a brute force powerful enough to uproot trees, hurdle vehicles through the air like they were toys, and level a home to splinters? No, than you probably are lucky enough to never have been caught in the midst of a twister.

Unfortunately, some know all too well about tornadoes and cyclones, especially if they happen to reside in a particular United States based hotbed rightfully named, Tornado Alley. But, to the rest of the world, tornadoes are nothing more than a curious oddity, often witnessed upon something safe, like a television or computer screen. So, that being said, let's discuss tornado formation.


If you have already seen the movie Twister, with Helen Hunt and Bill Paxton, you may think you know all there is about tornadoes. So, lets set the record straight. First, tornadoes do not growl or snarl, although they do sound much like a freight train rolling by, which could be mainly due to the massive vortex churning inside. Next, cars usually don't win during a race against a tornado. Tornadoes are quite commonly tracked hitting land speeds between forty-five and seventy five mph, so if your really think you can dodge traffic, falling debris, possible hail the size of your fist, all while maintaining a break neck speed, good luck!

Tornadoes are basically a large column of violently rotating air that spans all the way up into a storm system known as a super cell. The average tornado reaches wind speeds of 100 to 200 mph, but is easily capable of reaching velocities well exceeding 300 mph. Most tornadoes have a life span of about ten to twenty minutes, although given the right circumstances they can last much longer. Tornadoes can take on many appearances, ranging from a thick vertical fat funnel, to a long thin meandering rope draped across the sky.

Tornadoes are often part of a massive storm system, which is often accompanied by hale stones, strong wind, and heavy precipitation. Should you ever see anything that may appear to be a funnel cloud formation, please contact your emergency services, and seek immediate shelter.


Almost all tornadoes are formed within a system known as a thunderstorm. This could be mainly due to the atmospheric conditions that extend across the upper and lower part of the storm. To form a tornado you need two important meteorological ingredients. First, you need warm, humid air, which for North America comes rolling up from the Gulf of Mexico. Next, you need cold, dry air, which is usually pushed from the north, like a cold front from Northern Canada.

As these opposing air masses collide, they cause a significant instability in the atmosphere. Now, if this system becomes injected with a change in wind direction (common with hot and cold fronts merging), followed by an increased wind sheer, it forms a horizontal rotation in the lower part of the atmosphere. This very unstable storm system is now well on
it's way to becoming a major storm cell, also known as a super-cell.

Now, as the lower atmosphere continues spinning it generates a cycle of rising and falling air, which will begin increasing rotational speed. Rising air within the updraft at this point begins to tilt the rotating air from horizontal to fully vertical, which is basically the heart of a newly formed funnel cloud. At this point the area of rotation can be anywhere between 1 to 8 miles wide, extending across a majority of the lower segment of the storm cell.

At this point the local news and weather stations are well under way issuing a series of tornado alerts, which means there is a high probability that a tornado may touch down. This stage of the storm development is critical, mainly due to the storm is now capable of dropping a funnel cloud to the ground, thus producing a fully formed tornado.


Much like snowflakes, no two tornadoes are exactly alike. Some are sluggish and large, with a span almost equal to that of a football field. Other times they may be fast moving, with a narrow cone, appearing almost snake-like. Tornado cloud formations are often very dark, with an almost green tinge, usually accompanied by lightning and hail. Often, tornado chasers consider hail a precursor, mainly due to it confirms moist air, and the presence of an updraft, which pushes moist air into the upper colder atmosphere that compresses the water into hard ice pellets. Given the right meteorological conditions, these updrafts are all capable of being converted into a rotational storm cell.

Another common storm trait that indicates a possible tornado is known as a wall cloud. Unstable storm systems like super cells often have a low hanging accessory cloud, usually towards the southwest part of the storm cell. Interestingly, wall clouds are usually absent of rain, but these cumulonimbus formations are one of the key indicators storm chasers look for when hunting for tornadoes. The wall cloud can also begin to rotate, developing funnel clouds capable of producing tornadoes.


A brilliant man by the name of Tetsuya
"Ted" Fujita developed a scale in which to measure the various wind velocities of any given tornado. Himself along with Allen Pearson were the first members to head the National Severe Storms Forecast Center. The Fujita
scale is still used to measure all tornadoes worldwide.

Category F0: This is a small class tornado with a wind velocity ranging between 40-72mph.

Category F1: This is a common class of tornado, and it can produce winds of 73-112mph. Minimal to medium damage.

Category F2: Wind velocities ranging at 113-157mph, now motor homes become play-toys, and freight cars can be flipped, and large trees can either be snapped of fully uprooted.

Category F3: This class tornado can really pack a hefty punch. Wind velocity reach, 158-206mph. Now homes can be torn apart, entire forests leveled, and heavy vehicles can be lifted straight off the ground.

These next three categories are unlike any other storms. They are the line that gets crossed between damage and destruction. Most tornadoes of this class are referred to as the "finger of God".

Category F4: This class is considered on the devastating range, with winds ranging between 207-260mph. With sustained winds of this magnitude well-constructed houses can be leveled to splinters, cars become missiles, and nearly everything in its path will sustain damage.

Category F5: The range class is considered incredible damage, and rightfully so. Velocity ranges between 261-318mph, they can lift even the strongest framed houses clear off their foundations. Steel reinforced concrete structures suffer extreme damage, and barely anything remains unscathed.

Recently due to severe weather patterns most scientists predict that storm severity is on the rise, mainly due to global warming, and a new class of super storms may be the result. This leads me to my final; and I hope I never see this day. The most inconceivable Tornado would be the Category F6. If F4 and F5 class are considered the "finger of God", than an F6 would undoubtedly be the Grim Reaper of all tornadoes. Theory suggests wind speeds would be 318-400mph, and damage would range to unimaginable. There are no structures in existence that have been designed to withstand the winds of an F6 tornado.

It is important to understand tornado formation to ensure you are properly prepared. Tornadoes are unpredictable and can form very quickly, with little to no warning at all. I highly recommend practicing tornado drills, since although your city may have had little to no contact; storms like these rarely follow the rules.

If caught indoors, try going to the lowest point, such as the basement. If your house does not come equipped, seek refuge in one of the middle rooms. Avoid walls, windows and doors; find an inner room like a bathroom or closet.

Outdoors, there can sometimes be little to no shelter. Find a ditch or culvert, stay low and cover your head and neck. Driving, don't stay in your vehicle, try to find any structure, or follow the above.

Storm systems like tornadoes deserve attention, because people need to know what they are capable of. There are no happy endings for most tornado victims. Homes and memories are lost, life and limb taken away, and all in a matter of minutes. My only hope for all, is that nobody has to ever come face-to-face with a tornado!

More about this author: Douglas Black

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