Is there a physical limit to the wind speed of a hurricane? If so, what is it?
• There is an upper limit on the velocity of any fluid, namely the speed of sound in the fluid, representing the speed at which a pressure wave propagates through it. Because such waves cause the molecules to move, they cannot travel faster than this (one can regard this as analogous to how information cannot travel faster than the speed of light).
For air at typical temperature and sea level pressure, the speed of sound is around 340 metres per second or 1224 kilometres per hour. However, winds in real weather systems never travel that fast. Apparently, the greatest sustained wind speed ever recorded was during Hurricane Allen in 1980, at 305 km/h – about one-quarter the speed of sound.
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Simon Iveson, The University of Newcastle, Callaghan, New South Wales Australia
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