Forces 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.
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
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.
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.
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. Approximately,
170 tornadoes are reported per year on land in Europe.
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 branch
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
Tornado Damage Scale
Developed in 1971 by T. Theodore Fujita of the University of
to the the original F-scale by a team of meteorologists and
wind engineers, to be implemented in the U.S. on 1 February
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
Put the lid on the jar and shake it vigorously for about 20
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
The tornado season has already begun in the United States.
Let us hope that Nature decides to keep its forces on leash this