ANSWERS: 4
  • Yes. "Wind blows because one large mass of air (called a high pressure area) moves towards and pushes under a large warm mass of air (called a low pressure area). If the earth was not spinning, the wind would always blow from the south in the Southern Hemisphere, and the from the north in the Northern Hemisphere, however the turning effect of the earth has a very important effect on the wind, called the Coriolis effect, deflecting the winds around the earth in different directions." ---http://www.schools.ash.org.au/paa1/coriolis.htm "Thunderstorms and sea breezes are big enough to be affected by Coriolis. In thunderstorms, the rotation can be seen in tornadoes. The direction of rotation of a tornado is determined by the rotation within the storm. This will be clockwise in the southern hemisphere." ---http://www.abc.net.au/northcoast/stories/s1000270.htm
  • No. What is accurate is that "MOST tornadoes spin counterclockwise in the northern hemisphere and clockwise in the southern." Tornadoes that spin clockwise in the N. hemisphere have been documented but are few and far between. What causes the spin direction is the storm-scale environment that the tornado forms in. Most storms in the N. hemisphere have similar environments due to the fact that the large scale environments are similar. It is incorrect to say the Coriolis determines the spin of a tornado. The Coriolis only affects things with a certain physical size or duration, and a tornado is too small and short-lived to be affected by the Coriolis. The Coriolis has a large influence on the large-scale environment the storm forms in, and the large-scale environment determines the storm-scale environment, which determines the direction of spin of the tornado...so it can be said the Coriolis indirectly influences the spin direction of a tornado. Most tornadoes form in the N. hemisphere with similar wind shear characteristics, which favor counterclockwise rotating thunderstorms, hence favoring counterclockwise rotating tornadoes.
  • YES! But there are exceptions. In answer - I once watched a satellite feed of several storm systems forming over the equator. From the photos, it was quite apparent that each storm system had a rotation to it (clockwise in the northern hemisphere, and counterclockwise in the southern). The reason storm systems rotate this way is complex, but you can understand it simply - by putting your hand out the window of a moving car. You feel the air resistance. When you move with the wind, you feel less resistance, against the wind - you feel more. The formation of these storm systems works in much the same way - only the system is your hand and the earth is the car. So, there is more resistance toward rotation counterclockwise in the northern hemisphere, and visa-versa for the southern. Yes, it is possible to go against that resistance, but even though this may happen on a small scale at times (tornados) - you will not likely ever witness one on a large scale (hurricane or the whole storm system). I know, speaking of a tornado as small scale seems a bit odd - but this is the WHOLE WORLD we are talking about - and it's spin is powerful beyond belief. 900 miles per hour at the equator - where most storm systems form. Can you imagine putting your hand out the window at 900MPH? Of course the weather is affected by that! A small object will feel less resistance to the wind, a bigger one will feel more. That's why some tornados can spin the other way - but storm systems don't. The bigger it is, the more resistance to opposing the spin of the earth it will have. I don't know if the following is under a specific scientific theory - but think about this for a second: The earth spins faster at the equator than the poles (the speed of an object in rotation increases the farther it is from the center of rotation). If I have a storm system 100 miles wide - then the side closest to the equator MUST be spinning faster than the side farther from the equator. It is precisely that difference in speed that causes storm systems to rotate in the first place. As faster air moves by, it creates a vacume of sorts, drawing in the slower air from much like an airplane wing is designed to create lift. To summarize - Most tornados do IN FACT rotate CW in the Northern, and CCW in the Southern Hemispheres. The reason for this is the Earth's rotation - and it's effect on the weather (the corolis effect).
  • Redneck savant has it right, but its just the opposite, most tornadoes spin counter-clockwise in the northern hemmisphere and clock-wise in the southern hemmispher.

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