A tornado is a violently rotating column of air extending between, and in contact with, a cloud and the surface of the earth. Generally spawned by thunderstorms, they have been known to occur with and without the presence of lightning.
The stronger tornadoes attain an awe-inspiring intensity, with wind speeds that exceed 200 miles per hour and in extreme cases may approach 300 miles per hour. Tornado wind speeds are estimated after the fact based on the damage they produce. Tornadoes are categorized on a scale of 0 (weakest) to 5 (strongest) according to the Enhanced Fujita Scale.
- Can come one at a time, in clusters, and they can vary greatly in length, width, direction of travel, and speed.
- Tornadoes can be one mile wide and stay on the ground over 50 miles.
- May appear nearly transparent until dust and debris are picked up or a cloud forms within the funnel.
- Waterspouts are tornadoes which form over warm water. They can move onshore and cause damage to coastal areas.
- If a tornado "watch" is issued for your area, it means that a tornado is "possible."
- If a tornado "warning" is issued, it means that a tornado has actually been spotted, or is strongly indicated on radar, and it is time to go to a safe shelter immediately.
- Be alert to what is happening outside; warning signs include:
- A sickly greenish or greenish black color to the sky.
- A strange quiet that occurs within or shortly after the thunderstorm. Clouds moving by very fast, especially in a rotating pattern or converging toward one area of the sky.
- A sound like a waterfall or rushing air at first, but turning into a roar as it comes closer (the sound of a tornado has been likened to that of both railroad trains and jets).
- Debris dropping from the sky.
- An obvious "funnel-shaped" cloud that is rotating, or debris such as branches and leaves being pulled upwards, even if no funnel cloud is visible.
- If there is a watch or warning posted, then the fall of hail should be considered as a real danger sign. Hail can be common in some areas, however, and usually has no tornadic activity along with it.
If you see a tornado and it is not moving to the right or to the left relative to trees or power poles in the distance, it may be moving towards you!