This report is on tornadoes, how tornadoes are formed, different types of tornadoes, American tornadoes and some facts on the subject of tornadoes.
What is a tornado?
A tornado, commonly known as a twister, is a violent spinning column of air. Tornadoes are numerous and devastating. During May in Central, Eastern and North Eastern USA, on average of five a day are reported. Tornadoes can spiral around at up to 450kph and can travel up to 100kph, leaving a path of destruction as it spins along. Tornadoes are actually very small and VERY violent. They very often occur in Tornado alley, which is an area that suffers tornadoes regularly.
How are tornadoes formed?
Tornadoes are formed in thunderclouds by the winds blowing in opposite directions. These winds create a spinning funnel of air, in which warm air rises at great speed. As this funnel tightens, the wind speed picks up.
The spiral of air comes down from the Thundercloud to the earth. Once on earth, the tornado acts like a big vacuum cleaner, sucking up anything that gets in its way. Two things help the tornado to spin violently: the Coriolis force and the jet stream. As the jet stream passes over the top of the storm, it adds an extra twist to the tornado. But as the twister goes along the tornado becomes weaker and eventually dies out.
How are tornadoes measured?
Tornadoes are measured with something called the Fujita scale:
THE FUJITA SCALE
Fujita ScaleRotational speed (KPH)Effects
F0 weakLess than 116Minor damage to buildings and trees
F1 weak117-180Minor damage to buildings and trees
F2 strong181-253Vehicles pushed off roads, roofs torn of buildings
F3 strong254-331Vehicle lifted off ground, severe damage to weaker buildings e.g. wooden houses
F4 violent332-418Vehicles picked up and carried over 2 km wooden and brick...