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1. Tornadoes and hurricanes are types of fast, powerful winds. ___
2. The USA has about one hundred tornadoes a year. ___
3. Tornadoes are either grey or white. ___
4. Hurricanes hit the western coast of the USA. ___
5. Hurricanes usually cause floods. ___
6. Hurricanes are rated by the Fujita scale. ___

Tornadoes and hurricanes

The United States has extremes of climate. Every year violent storms come across the sea or the land and wreck towns and cities.
Over 700 tornadoes hit the USA every year. Tornadoes are inland storms. A tornado (or twister) is a vortex of wind which spins violently and sucks up everything in its path – trees, cars and even houses and people.
Tornadoes come in many shapes and sizes, but are typically in the form of a visible funnel whose narrow end touches the ground with a small cloud of debris and dust. For a vortex to be classified as a tornado, it must be in contact with both the ground and a cumuliform cloud base.
In the United States, tornadoes are around 150 m across on average and stay on the ground for about 8 km. They can last from between five minutes to a couple of hours and the most extreme can attain wind speeds of more than 480 km/h. A strong tornado can change a house into a pile of matchsticks!
Tornadoes can have a wide range of colors, depending on the environment in which they form. Those which form in a dry environment can be nearly invisible: they can be gray to white and darker, taking on the color of debris. Tornadoes in the Great Plains can turn red because of the reddish tint of the soil, and tornadoes which occur near the time of sunset can be many different colors, appearing in hues of yellow, orange, and pink.
Tornadoes frequently develop in tropical areas close to the equator, but the vast majority in the world occur in the Tornado Alley region of the USA. The Fujita scale rate tornadoes by damage caused.
Hurricanes are tropical cyclones, occurring in the North Atlantic Ocean or the Northeast Pacific Ocean. Every year hurricanes hit the coast of the USA. These storms form off the coast of Africa and move across the Atlantic. They can be between 300 and 3,000 kilometres wide. Sometimes they lose power and die down when they reach the land. Sometimes they last for a week. In 1900 a hurricane destroyed Galveston, Texas and killed 6,000 people. The winds blew at 160 km/h and caused huge tidal waves which covered eyerything.
The centre of a hurricane is called ‘the eye’. Inside the weather is usually calm, but around the eye winds spin at a speed of up to 360 km/h. In Miami there is a national Hurricane Center which monitors pictures of storms and tries to predict what part of the coast.
 

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