Polar cyclone

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Polar cyclones (also known as Arctic Cyclones) are vast areas of low pressure. They should not be confused with what are commonly referred to as polar lows. Polar cyclones are essentially the same as tropical cyclones, however they are rarely as intense.

A polar cyclone is a low pressure weather system usually spanning 1,000–2,000 kilometers in which the air is circulating in a counter-clockwise fashion (in the northern hemisphere). The reason for the rotation is the same as tropical cyclones, the Coriolis effect.

Polar cyclones generally only last for around 2-3 days, and have average wind gusts of under 200km/h for the most severe cases. This falls short of tropical cyclones by a considerable margin, with tropical cyclones lasting for up to well over a week, while category 5 Cyclones (the most severe official category), can be accompanied by winds of over 300km/h in some cases.

Although cyclonic activity is most prevalent in the Eurasian Arctic with approximately 15 cyclones per winter, polar cyclones also occur in Greenland and the Canadian Arctic.

The Australian and US Federal Governments recently awarded funding for a study into what the affects of polar cyclones might be on drought in Australia. Scientists hope that the study will gleam a valuable insight into why droughts in Southern Australia are getting worse, and wether or not there is a direct link between polar climate activity, and weather patterns elsewhere. One of the big problems we have in planning for drought has to do with understanding whether the drought that we are in right now is a climate-change signal or part of a natural cycle. If we want to understand that we need to understand where the rain is coming from." ^[1] The study is expected to be complete by late 2010.

Polar cyclones can occur at any time during the year. However, summer cyclones tend to be weaker than winter cyclones. They are not well studied and seldom destructive as they typically take place in sparsely populated areas. The only infrastructure damage that occurs as a direct result of a polar cyclone, are to oil and gas rigs present throughout the Antartic ocean (sometimes known as the Southern ocean). Some cargo and shipping vessels are also affected, although there are minimal or no reports of losses in recent years as the result of a polar cyclone.