Frequently Asked Questions (FAQ)

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Definitions

10. What does 'maximum sustained winds' mean? How does it relate to wind gusts in tropical cyclones?

The Bureau of Meteorology uses a 10 minute averaging time for reporting the sustained (i.e. relatively long-lasting) winds. The maximum sustained wind are the highest 10 minute surface winds occurring within the circulation of the cyclone. These surface winds are those observed (or, more often, estimated) to occur at the standard meteorological height of 10 m having an unobstructed exposure.

Gusts are a wind peak lasting for just a few seconds. Typically, in a cyclone environment the value for a peak gust is about 25 % higher than a 10 minute sustained wind. See the Barrow Island and Mardie sustained wind and wind gust profile during TC Monty (2004).

NOTE: USA agencies, who have responsibility for issuing tropical cyclone warnings in the Atlantic and Northeast Pacific tropical cyclone basins, use a 1 minute averaging time for sustained winds. While one can utilize a simple ratio to convert from peak 10 min. wind to peak 1 min. wind (roughly 12% higher for the latter), such systematic differences tend to make inter-basin comparison of tropical cyclones around the world problematic.