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O P E N  F O R U M

  T H E   U N T A M E D


      

Uncontrollable
                 
 Forces of  Nature
uncontrollable forece of nature

Avalanches - Droughts - Earthquakes - Flooding - Fog and Mist - Forest Fires - Hurricanes - Landslides - Monsoons  - Severe Storms - Snowstorms - Tornadoes - Tsunamis - Volcanoes - Windstorms

Let’s look at one of these forces: Tornadoes.

Etymology

The word “tornado” comes from the Spanish word for “turned”, which in turn comes from the Latin word torqueo, meaning “to twist.” The Latin word derives from the PIE root tar–, and is etymologically related to the Norse Thor. Some common, related slang terms are: twister, whirlwind, wedge, funnel, finger of God, Devil’s tail, rope, or stovepipe.

Meaning
According to the Glossary of Meteorology (AMS 2000), a tornado is “a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud.”  Literally, in order for a vortex (a whirling mass of air) to be classified as a tornado, it must be in contact with the ground and the cloud base.

Cause
The most destructive and deadly tornadoes occur from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. Tornado formation is believed to be caused mainly by things that happen on the storm scale, in and around the mesocyclone. Recent theories suggest that once a mesocyclone is underway, a tornado develops  with differences in temperature across the edge
of downdraft air wrapping around it.

Mathematical modelling studies of tornado formation also indicate that it can happen without such temperature patterns. In fact, very little temperature variation was observed near some of the most destructive tornadoes in history, for example, the Great Plains tornado outbreak on 3 May, 1999.

Areas
Tornadoes have been witnessed in every continent except Antarctica. However, a major percentage of the world’s tornadoes occur in the United States. This is mostly due to the unique geography of the country, which allows the conditions which breed strong, long-lived storms to occur many times a year. Other tornado-prone regions of the world are the Netherlands, followed by the United Kingdom (especially England), Bangladesh, India, Argentina, Italy, Australia, New Zealand, Germany, Estonia, and portions of Uruguay. Occasional strong tornadoes occur in Russia, France, Spain, Japan, and portions of Paraguay and Brazil. Tornadoes have hit South Africa and parts of Pakistan in 2001 as well. On April 4 2006, a rare F2 tornado hit northwestern Israel. Approx
imately, 170 tornadoes are reported per year on land in Europe.

Destruction
The average tornado has a diameter of about 200 to 300 yards, and some grow large enough to spawn smaller tornadoes known as satellite tornadoes. These small offspring, about 50 yards across, can be very fierce and do lots of damage. They also tend to br
anch away from the parent funnel, taking separate paths across the earth.

A tornado can form very quickly, sometimes in a minute or less. It can travel across the ground at high speeds, and then just as suddenly vanish. They can kill in a matter of seconds.

Most tornadoes last less than twenty minutes and travel less than 15 miles. However, superstorms sometimes occur, traveling over 100 miles before they are exhausted. Although they don’t occur very often, they are responsible for 20% of all tornado casualties.

On average, the United States experiences 100,000 thunderstorms each year, resulting in more than 1,200 tornadoes and approximately 50 deaths per year. Every year, twisters in the United States cause about US$500 million worth in damage!

This is a sample scale to measure the damage done by a tornado

Fujita Tornado Damage Scale
Developed in 1971 by T. Theodore Fujita of the University of Chicago
 

SCALE   WIND ESTIMATE
(MPH)
 
TYPICAL  DAMAGE
F0 <73  Light damage
F1 73-112  Moderate damage
F2 113-157  Considerable damage
F3 158-206 Severe damage
F4 207-260 Devastating damage
F5 261-318 Incredible damage
An update to the the original F-scale by a team of meteorologists and wind engineers, to be implemented in the U.S. on 1 February 2007.  

Create your own Tornado!
Fill the glass jar about 3/4 full of water (for that ‘Wizard of Oz’ effect, throw in a few Monopoly houses).


Add some food coloring along with about a teaspoon of dishwashing detergent.

Put the lid on the jar and shake it vigorously for about 20 seconds.

Now, give the jar a good twist.

The liquid inside the jar will form a vortex or funnel that would look and act just like a real tornado. The tornado’s body will even lengthen and contract just like the real one!

Now keep praying hard that your miniature tornado does not turn lifesize!!

The tornado season has already begun in the United States. Let us hope that Nature decides to keep its forces on leash this year...

 

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