A TORNADO IS A NARROW, FUNNEL SHAPED COLUMN OF SPIRALING WINDS THAT EXTENDS DOWNWARD FROM THE CLOUD BASE AND TOUCHES THE GROUND.
The funnel of the tornado is a mixture of clouds and dust that form around an area of intensely low pressure.
TORNADOES FORM WHEN mT AIR MASSES FROM THE GULF OF MEXICO COLLIDE WITH cP AIR MASSES MOVING DOWN FROM CANADA.
Under these conditions the atmosphere becomes extremely unstable. The rapidly rising warm air causes high altitude horizontal winds to swirl, then tilt to a vertical position.
When the funnel cloud reaches the Earth we call it a tornado. Since they are Low Pressure systems, the winds in a tornado all spin counterclockwise and move in towards the center of the tornado. The strongest winds in a tornado approach 500 kph, but because they move so fast it is hard for us to directly measure them. Instead we use the Enhanced Fujita or EF Scale to estimate the wind speeds in a tornado based on the observable damage done.
Once on the ground tornadoes do not typically last more than an hour before they fall apart. While they are short lived, they are incredibly dangerous because of the wind speeds and debris thrown around in them. Add to that the unpredictability of their irregular path, and tornadoes become very scary.
Because they are so dangerous, unpredictable, and fast moving, cities and towns issue different types of alerts when there is a risk of tornadoes.
Watches are issued when the conditions for tornado formation are present, and they are likely to form.
Warnings are issued when a tornado has touched down on the ground in the area.
When a tornado warning is issued it is recommended that you go inside and get to the lowest point indoors possible, avoid windows, and cover your eyes, neck and head until the tornado passes.