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- Bu səhifədəki naviqasiya:
- Tornadoes are among the most violent storms on Earth, with the potential to cause very serious damage.
- F2 (113-157mph)
- F4 (207-260mph)
1 How a tornado is formed Although no two tornadoes are the same, they need certain conditions to form - particularly intense or unseasonable heat. A storm quickly develops - there may be rain, thunder and lightning.
As the ground temperature increases, moist air heats and starts to rise.
2 How a tornado is formed When the warm, moist air meets cold dry air, it explodes upwards, puncturing the layer above. A thunder cloud may begin to build. A storm quickly develops - there may be rain, thunder and lightning. 
3 How a tornado is formed Upward movement of air can become very rapid. Winds from different directions cause it to rotate. A visible cone or funnel drops out of the cloud towards the ground.
4 How a tornado is formed The vortex of winds varies in size and shape, and can be hundreds of metres wide. A tornado can last from several seconds to more than an hour and may travel dozens of miles.
5 How a tornado is formed Winds within the tornado may be so fast they cannot be properly measured. Instead, the Fujita damage scale is used to estimate speed. F0 (0-73mph) - Light damage: Some damage to chimneys. Branches broken from trees and some trees blown over. F1 (73-112mph) - Moderate damage: Moving cars blown off roads, mobile homes overturned, or pushed off their foundations.
demolished, large trees snapped or uprooted, cars lifted off the ground.
trees uprooted, heavy cars thrown, walls of homes destroyed. F4 (207-260mph) - Devastating damage: Well constructed buildings destroyed, large objects thrown. F5 (261-318mph) - Incredible damage: Cars thrown more than 100 metres, strong buildings swept away. Yüklə 8,14 Kb. Dostları ilə paylaş:
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