MAIN Science Meteorology Tornadoes

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

• If you see a tornado, seek cover in a safe shelter.

• 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 large open spaces such as school gymnasiums or open areas in malls and shopping centers. If caught on the road during a tornado, evacuate your car immediately and take shelter in a ditch or culvert.

More about tornadoes around the Web:

Tornadoes ... Nature's Most Violent Storms - 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 - 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.

National Geographic - Tornadoes - Stunning photos and videos, plus related news & feature stories, safety tips.

The Online Tornado FAQ - Extensive Q&A on tornado basics, forecasting, tornado spotting & chasing, related scientific research, historic tornadoes, safety guide.

FEMA for Kids - Tornadoes - Kid-friendly facts, photos and information about tornado dangers including safety tips, first-person accounts, tornado drawings, related games & video.

Tornado in a Bottle - Fun & fascinating science class project with complete instructions and materials list for creating a vortex using two soda bottles.

also see -> Hurricane safety tips | Camping & Weather Safety Tips