Facts About Tornado

• Tornados, or twisters as they are often called, are rapidly rotating columns of air, many times in a funnel shape, which touch the earth. They most often hang down from cumulonimbus clouds and can cause much damage on the ground.
• Tornados may form when a warm front meets a cold front forming a thunderstorm which can spawns one or more twisters. But, this is an oversimplification. Rotating thunderstorms called mesocyclones are the best predictors of tornadic activity.
• Mesocyclones are also called supercells and are well defined thunderstorms on radar. Supercells may also include hail, severe winds, lightning and flash floods.
• Most twisters or cyclones travel from southwest to northeast, though this is not always the case. Some can move in the opposite direction for short periods and may even backtrack if hit by winds from the thunderstorm's core.
• Funnel clouds usually last less than 10 minutes before dissipating with many only lasting several seconds. On rare occasions, cyclones can last for over an hour as many were reported to have done in the early 1900's. (source: tornadofactsdotnet)