A tornado is a rotating column of air that extends from the base of a thunderstorm cloud to the ground. Tornadoes occur when cold dry air blow in from the west. Colder higher air blows in from the north. Warm west air blows in from the south. The warm air is low to the ground. Usually warm air rises. When two layers of colder air is above it the warm air can't rise. The cold air doesn't drop like it normally does. The air begins to twirl against each other making tall clouds and strong winds. Finally some warm air may punch a hoel into the cold air. This rising warm air cools causing rain and hail. Large hail often comes before the tornado. Then the cloud may start to spin. This is a funnel cloud. A funnel cloud becomes a tornado when it touches the ground. Tornadoes are classified using the Fujuita Scale. A team of meteorologists and engineers survey the damaged path, measuring the length and width, and study the most severe damage to estimate the tornado winds. They then rank the tornado from 0 through 12 based on the type of wind damage. Tornadoes speeds do not usually go above the F-6 rating.
The best protection from a tornado is to know that one is on its way. When a tornado is a possibility a tornado watch is issued for the area. If a tornado is spotted by radar or by a person a warning is issued. One good way to be informed if a tornado watch or warning is in effect is to use a weather radio. This radio broadcasts the latest weather from the National Weather Service. The messages are repeated every 4 to 6 minutes and are updated every 1 to 3 hours. If a storm is approaching the messages are updated more frequently. Most stations operate 24 hours daily. Knowing what to do when a tornado warning takes place can save lives. Plan and in-house shelter. The basement is the best shelter. This shelter needs to be strong enough to remain intact if winds carry away large portions of the house. It also needs to be able to withstand flying debris.
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