Of course, we are all quite accustomed to thunderstorms. These are usually local storms. But there are certain kinds of storms that may cover thousands of square miles. One such type is called a "cyclonic storm" or "cyclone".
In a cyclone, the winds flow towards the centre of an area of very low pressure.
A curious thing about them is that the winds flow in spiral fashion. In the Northern Hemisphere such storms turn anti-clockwise, in the Southern Hemisphere they turn clockwise!
A tornado is simply a special kind of cyclone. A tornado arises when the conditions that cause ordinary thunderstorms arc unusually violent. There is an updraft of air. There are winds flowing in opposite directions around this rising air. This starts a whirling effect that is narrow and very violent. When this happens, centrifugal force throws the air away from the centre. And this leaves a core of low pressure at the centre.
This low-pressure core acts like a powerful vacuum on everything it passes. This is one of the destructive things about a tornado. It can actually suck the walls of a house outwards in such a way that the house will collapse. The other destructive thing about a tornado is the high winds that may flow around the edges of a whirl. These winds can reach 300 miles per hour and nothing is safe against them.
In a cyclone, the winds flow towards the centre of an area of very low pressure.
A curious thing about them is that the winds flow in spiral fashion. In the Northern Hemisphere such storms turn anti-clockwise, in the Southern Hemisphere they turn clockwise!
A tornado is simply a special kind of cyclone. A tornado arises when the conditions that cause ordinary thunderstorms arc unusually violent. There is an updraft of air. There are winds flowing in opposite directions around this rising air. This starts a whirling effect that is narrow and very violent. When this happens, centrifugal force throws the air away from the centre. And this leaves a core of low pressure at the centre.
This low-pressure core acts like a powerful vacuum on everything it passes. This is one of the destructive things about a tornado. It can actually suck the walls of a house outwards in such a way that the house will collapse. The other destructive thing about a tornado is the high winds that may flow around the edges of a whirl. These winds can reach 300 miles per hour and nothing is safe against them.
