Storm systems thousands of kilometres away can generate large waves that reach New Zealand. This satellite photograph shows a storm system (the spiralling clouds just south of Tasmania) developing at latitudes between 40° and 50° south – known as the roaring forties. Intense depressions (air masses that are unstable and ascending) suck in air towards their centre as they spin eastwards. If one of these depressions sits just south of the country, and is slow moving, it can pump high winds and big waves onto exposed coasts.
Te whakamahi i tēnei tūemi
Metservice New Zealand
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