Tornado is derived from the Spanish word 'tronada', which means 'to thunder'. It is the strongest known atmospheric disturbance with the wind velocity exceeding 300 km/hr. The most frequented tracks of tornadoes are in the Mississippi valley in the US.They are also called 'Twisters' because they twist whatever that comes in their way and bring large-scale devastation. Tornado carries soils, dust and debris also. It pulls up trees and destroys everything that comes in its way. It kills animals also. It destroys vegetation also. It flattens small hills causes to collapse weak rocks and dilapidated houses.