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Roaring Forties
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strong westerly winds found in the Southern Hemisphere
~5 min read
Encyclopedic overview
Roaring Forties as they contract towards southern Australia (observed in September 1895).
The Roaring Forties are strong westerly winds that occur in the Southern Hemisphere, generally between the latitudes of 40° and 50° south. The strong eastward air currents are caused by the combination of warm air being displaced upward from the Equator towards the South Pole, Earth's rotation, and the scarcity of landmasses to serve as windbreaks at those latitudes. On average, winds speeds in the region measure around 10 m/s (22 mph) with peak gusts of over 25 m/s (56 mph).
Excerpted from Wikipedia’s “Roaring Forties” article, available under the CC BY-SA 4.0 licence.