Although a tornado can hit at anytime of year, the transitional months of spring and fall - when a cool front meets a warm front - usually spells thunderstorms.
Thunderstorms, in turn, are the breeding ground for tornadoes as high winds rapidly swirl to create a violent vortex of rapidly spinning winds that can cut a swath of destruction for miles around.
The larger the thunderstorm the greater chance of tornado funnels forming, especially where atmospheric conditions result in sudden and violent changes of wind direction and speed.
Since evidence of drastic changes in weather patterns continue to emerge as a result of global warming, scientists further predict an upsurge in tornadoes in differing parts of the world in the years ahead.
How tall is a tornado compared to a major NYC landmark?
(Hint: place your cursor over the image.)
USA - Tornado Central
While tornadoes in varying strengths can form anywhere, the United States is home to the most violent and destructive tornadoes on the planet causing almost 100 fatalities and more than 1,500 injuries each year.
This is especially true of the Tornado Alley region encompassing a large swath of the southern and midwestern U.S.
Tornado warning signs
From the ground, the most common warning signs that a tornado may
be forming is when dark clouds (accompanied by lightning strikes) begin to take on an ominous green color, and when large hail begins to fall. Along with the visual evidence, the terrifying sound of a tornado has often been likened to that of a roaring freight train.
Tornado preparedness & safety tips
• At home, always avoid an upstairs room which is more susceptible to collapse from high winds. The basement is best, or else take shelter in a room surrounded by other rooms for added protection.
• In schools, offices or public buildings, opt for shelter in interior rooms on the ground floor or basement. Avoid open spaces such as school gymnasiums or large open concourses in malls and shopping centers. The more walls between you and the tornado the better!
• If you see a tornado while driving on the road, it's always safest to drive at a right angle to its movement (if it's heading west, drive to the north, for example.) On a highway, seeking shelter under an overpass seems logical, but winds are usually amplified under these structures -- bringing with it dangerous debris at high speeds -- so its best to seek cover in a ditch or lower ground if a strike is imminent.
Severe Weather 101 - Here's an excellent illustrated overview with information on what causes tornadoes and how they form, tornado facts & myths, clues as to when a tornado may strike, safety tips & advice, guides to related disaster plans for schools, families and institutions.
The Tornado Project - Check out a digital library of facts & information including tornado myths & oddities, personal tornado stories, tornado chasing, safety tips & advice, lists of most powerful and destructive tornadoes, online store offering tornado books, videos.