What causes gusts of wind? © Getty Images

What causes gusts of wind?

Leave the umbrella down for this one. Friction, atmospheric pressure and air warming can all play a part in sudden bursts of wind.

Asked by: Ron Baker

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Gusts are sudden but short-lived increases in the speed of the wind. They’re often created as wind brushes past buildings, trees or other obstacles, with the friction causing it to slow and then speed up again.

Larger-scale variations in the direction or speed of wind (known as wind shear) can also create chaotic changes in atmospheric pressure, generating gusts as the air flows from high to lower pressure. Finally, as the Sun warms up a surface, the overlying air warms and rises, which also creates gusts as cooler, denser air rushes downward in its place.

The higher the average wind speed, the gustier it is likely to be. This relationship depends on the local terrain, though: towns and cities generate more gusts through friction and solar heating. For the same average wind speed, urban areas are therefore likely to see much stronger gusts than open landscapes.

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