where we hope you learn about the fascinating weather that affects us day to day. This is a great learning resource for parents and teachers.
What is a tornado?
- A tornado is a very violent windstorm.
- In a tornado the air is concentrated (pushed together).
- The air whirls upwards rapidly.
- A tornado is grey in colour and looks like an elephant’s trunk swaying down from the clouds to touch the ground with its tip.
- A tornado is only a tornado if it touches the ground. If the tip of the ‘elephant’s trunk’ does not touch the ground, the storm is known as a funnel.
- A tornado moves across the country. It moves at a speed of between 25 and 90 miles per hour.
- It can cause much destruction.
Where do tornadoes happen?
- Tornadoes happen in every continent of the world.
- The most dangerous tornadoes happen in the southern states of the USA.
- There is an area through Texas, Oklahoma, Kansas, Nebraska and Dajkota which is called Tornado Valley.
- In the central areas of the continent of America there are usually about fifty tornadoes a year.
- There have been some very small tornadoes in Britain that have damaged buildings, but this is unusual.
How big is a tornado?
- A tornado usually has a diameter (the measurement from side to side) of only 25 to 50 yards.
What causes a tornado?
- Scientists are not sure of all the causes of tornadoes.
- Tornadoes happen when a cold wind high up meets warmer air and warmer winds lower down.
- This causes the winds to swirl and the warmer air from below rushes upwards at terrific speed.
- As the tornado moves forward, this warm wind rushing upwards can pick up any objects in its path. (Look below for a description of the tornado that hit Annapolis in 1925.)
What is the difference between a tornado and a hurricane?
- A hurricane can be as much as 400 miles from side to side.
- A tornado is much smaller, with a diameter of no more than 50 yards.
- A hurricane has a small area in the centre, known as ‘the eye of the storm’, which is calm. If you are in the centre, or eye, of a hurricane, there is dead calm and a blue sky above you.
- A tornado has a centre core of violent ascending currents of air. The centre of the tornado is the most dangerous part.
- A hurricane forms first at sea and can move towards the land.
- Tornadoes are formed on land. A storm like a tornado but which forms at sea is called a waterspout.
What damage can a tornado do?
This photograph from 2007 shows the damage a tornado can do!
Some tornadoes have caused terrible damage and loss of life. One of the worst was in March 1925 when a tornado hit the town on Annapolis in Missouri, USA.
It was a calm sunny afternoon and children were playing marbles in the street. The sky was clear and blue. Suddenly on the horizon people saw a black cloud shaped like an ice-cream cone. It raced down on the town at terrific speed, bringing with it a wind of 150 miles an hour.
With a deafening roar the tornado tore through the streets, leveling everything in its path. Solid stone buildings were torn apart, passenger trains were turned over and smashed, fifty cars were swept up and carried over the rooftops.
The tornado’s path was less than 250 yards wide but it left a terrible scene behind it, with 823 people killed and nearly 3,000 injured.
People who live in Tornado Valley in America build cellars, or storm shelters, beneath their homes so that they can take shelter if a tornado comes.