In dealing with weather there are many types which can seriously cause damage
to people and communities. Especially in the aviation we as pilot have to take
into account many consideration in preparing for a flight. For instance,
thunderstorms, icing levels, winds aloft, and visibility all play major factors
in preparing for a flight.
But there are some weather phenomena that can be extremely dangerous to fly
into. Hurricanes, wind shear, and tornadoes are just some of the major
threatening systems that can cause serious damage to people and places. One of
the most interesting systems is the tornado. So what is a tornado? A tornado is
a violently rotating column of air, which is found below cumulonimbus clouds and
is nature's most violent wind. A tornado is officially defined as an intense,
rotating column of air extending from the base of a thunderstorm cloud to the
ground. Wind speeds in tornadoes can vary from 72 to almost 300 mph.
Fortunately, only 2 percent of all tornadoes have winds greater than 200 mph.
When a tornado is seen and has not yet made contact to the surface this is what
is called a funnel cloud. When a funnel cloud touches the ground, it becomes a
tornado (Jack Williams, USA TODAY Information Network). Most tornado's range
from 300 to 2,000 feet in diameters, but have been reported to extremes of one
mile. Tornado's usually travel in a southwest to northeast direction at about 30
knots in the U.S.
According to Peter F. Lester tornado's lifetime average only for a few
minutes, but have been documented to last over three hours. In the United States
there is one particular place that seems to be more prominent to have tornado's
form. The American Meteorology Society's Glossary of Weather and Climate defines
Tornado Alley as: The area of the United States in which tornadoes are most
frequent. It encompasses the great lowland areas of the Mississippi, the Ohio,
and lower Missouri River Valleys.
According to USA today Depending on the time of year, the southern and
northern borders of tornado alley extend from about central Texas to Nebraska
and Iowa. This region is where tornadoes spin up most frequently and where most
monster, mile-wide twisters roam. The question is why is this area so prime for
tornado's to form? Thunderstorms thrive on lots of warm, humid air. And the
rotating thunderstorms, called supercells, which spawn the biggest tornadoes,
need low-level winds that shift direction and grow stronger just above the
ground (USA weather).
The Gulf of Mexico provides an abundance of tropical moisture blowing into
the Plains on south and southeast winds. Meanwhile the higher and drier
elevations of the Rockies allow a hot, dry layer of air to blow over the region
from the southwest.
