Tornado

What is tornado?

A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters or cyclones, although the word cyclone is used in meteorology, in a wider sense, to name any closed low pressure circulation. Tornadoes come in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 110 miles per hour (177 km/h), are about 250 feet (76 m) across, and travel a few miles (several kilometers) before dissipating. The most extreme tornadoes can attain wind speeds of more than 300 miles per hour (483 km/h), stretch more than two miles (3.2 km) across, and stay on the ground for dozens of miles (more than 100 km).

Oklahoma Tornado (Watch here)

Condensation

A tornado does not necessarily need to be visible; however, the extremely low pressure caused by the high wind speeds and rapid rotation usually causes water vapor in the air to condense into a visible condensation funnel. The tornado is the vortex of wind, not the cloud condensation.

Tornado family 

A single storm may produce multiple tornadoes and mesocyclones. Tornadoes produced from the same storm are referred to as a tornado family. Sometimes multiple tornadoes from distinct mesocyclones occur at the same time.

Tornado outbreak 

Occasionally, several tornadoes are spawned from the same very large storm. If there is no break in their activity, this is considered a tornado outbreak, although there are various definitions. A period of several successive days with tornado outbreaks in the same general area (spawned by multiple weather systems) is a tornado outbreak sequence, occasionally called an extended tornado outbreak.

Severe tornado outbreaks 

Sometimes, tornadoes happen in groups. 148 tornadoes struck on the same day in April 1974. Many towns in Midwestern America and Canada were destroyed. More than 300 people died. They were hit by flying wrecks, buried under houses, and thrown by powerful winds. That day, students in Xenia, Ohio were practicing for a play in the auditorium stage. One girl looked out the window and saw the tornado. The students ran into the hall, covering their heads. A few seconds later, all the school buses flew right onto the stage.

 

A man in another town hid under the couch in his living room. He held onto one couch leg. The tornado struck his house, and winds blew around him. When the tornado left, he was outside. There was no house. The couch had disappeared, and he was only holding onto one couch leg.

Tornado Watch

A "tornado watch" is given when the weather conditions look like a tornado could form. A 'PDS (Particularly Dangerous Situation)' watch is given when a likely tornado outbreak is to start, many strong tornadoes will form in the area, or an ongoing tornado outbreak is in the works in the area.

Tornado Warning

 A "tornado warning" is given if somebody has actually seen a tornado or if a tornado 'signature' (usually the storm has a 'hook' or 'U' echo) has shown up on radar.

Tornado Emergencies

Tornado emergencies are a special weather statement saying that a powerful tornado is about to hit an area with a lot of people in it (cities like Nashville, TN), a tornado has been spotted, and the tornado is expected to cause deaths.

Safety tips

To keep safe in a tornado, here are some tips you can follow:

• Go to the lowest floor of the building. Stay close to the center of the building and away from windows, for example a bathroom with no windows and get in to the bath tub.
• Find a piece of strong furniture or a mattress to go under or hide in a closet and wait until it is over.
• If you are in a school, do not go to the gymnasium or any other place that has a high ceiling. Squat near the wall, placing your hands on the back of your head.
• If you cannot find shelter, find the lowest, most protected ground and cover your head with your hands.

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