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1. What is a tornado?

A tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes are the most violent of all atmospheric storms.

2. When are tornadoes most likely?

Tornado season usually refers to the time of year the U.S. sees the most tornadoes. The peak "tornado season" for the Southern Plains is during May into early June. On the Gulf Coast, it is earlier during the spring. In the Northern Plains and Upper Midwest, tornado season is in June or July. But, remember, tornadoes can happen at any time of the year. Tornadoes can also happen at any time of day or night, but most tornadoes occur between 4-9 p.m.

3. Where do tornadoes occur?

Tornadoes occur in many parts of the world, including Australia, Europe, Africa, Asia and South America. Even New Zealand reports about 20 tornadoes each yer. Two of the highest concentration of tornadoes outside of the U.S. are Argentina and Bangladesh.

4. How do tornadoes form?

The truth is that National Weather Service don't fully understand. The most destructive and deadly tornadoes occur from super cells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. (Supercells can also produce damaging hail, severe non-tornadic winds, unusually frequent lighting, and flash floods.) Tornado formation is believed to be dictated mainly by things which happen on th storm scale, in and around the mesocyclone. Recent theories and results from the VORTEX2 program suggest that once a mesocyclone is underway, tornado development is related to the temperature difference across the edge of downdraft air wrapping around the mesocyclone. Mathematical modeling studies of tornado formation also indicated that it can happen without such temperature patterns; and in fact, very little temperature variation was observed near some of the most destructive tornadoes in the history on May 3, 1999.

5. What is straight-line wind?

Straight-line wind is a term used to define any thunderstorm wind that is not associated with rotation, and is used mainly to differentiate from tornadic winds.

6. What is a downburst?

A downburst is a result of a strong downdraft. A downburst is a strong downdraft with horizontal dimensions larger than 4 km (2.5 mi) resulting in an outward burst or damaging winds on or near the ground. (Imagine the way water comes out of a faucet and hits the bottom of the sink.) Downburst winds may begin as a microburst and spread out over a wider area, sometimes producing damage similar to a strong tornado. Although usually associated with thunderstorms, downbursts can occur with showers too weak to produce thunder.

7. How many tornadoes occur in the U.S. each year?

About 1,200 tornadoes hit the U.S. yearly. Since official tornado records only date back to 1950, we do not know the actual average number of tornadoes that occur each year. Plus, tornado spotting and reporting methods have changed a lot over the last several decades.