Arctic Cyclone

Picture an enormous pinwheel of wind, cloud, and bitterly-cold snow whirling above thousands of square miles of northern sea and land -- a frosty equivalent of the hurricane -- and you have a good mental image of an Arctic cyclone. Alternately called polar cyclones, Arctic cyclones are enormous low pressure systems found in the Arctic and Antarctic regions of the globe. Although most people never experience an arctic cyclone, and their fury is mostly spent on remote, uninhabited seas and coasts, these cyclones play an important part in the grand weather patterns of the Earth, and are coming under increased scientific scrutiny for this reason.

Arctic cyclones spin counterclockwise in the northern regions and clockwise in the Antarctic, responding to the Coriolis effect like any other weather system. They can be up to 1,200 miles wide -- large enough to fill a good portion of the North American continent, were they ever to drift that far south -- but their influence on the temperate world's weather, however well-documented, is largely indirect.

Arctic cyclones -- a year-round phenomenon

Arctic cyclones may vaguely resemble hurricanes, but they are different from them in several important ways. One of these ways is that they do not have a 'season.' Everyone is familiar with the hurricane season in the Gulf of Mexico -- a gradual increase in the number and vigor of hurricanes through the late summer, peaking in the early autumn. However, Arctic cyclones occur all year long, summer or winter.

Summer witnesses more frequent but much weaker Arctic cyclones, while winter's cyclones are more uncommon but tend to be stronger. Research suggests that Arctic cyclones have become more frequent over the past fifty years -- perhaps as a result of global warming, or maybe as a result of some climate mechanism that isn't yet understood because it hasn't been studied long enough yet.

The most frequent area for Arctic cyclones to occur in the northern hemisphere is the Eurasian arctic, above Russia and Siberia. They also form over Greenland and the Canadian arctic, although less often. In Antarctica, Arctic cyclones typically occur in the vicinity of the Ross Ice Shelf. The birthplace of these cyclones is based on the combination of temperature, water currents, air flow over nearby land masses, another other processes which influence their creation. The best conditions for cyclone genesis is when an extremely cold low pressure area passes over warmer waters, sucking up moisture from the surface and turning it into clouds and snow.

The behavior of Arctic cyclones

Arctic cyclones tend to be rather chaotic entities, moving randomly through the polar regions and lasting for anywhere from a few days to several weeks. Since their motions are completely random and unpredictable, it would be impossible for forecasters to predict their behavior even if there were a reason to do so (that is, if they occurred in inhabited regions rather than remote, deserted polar regions).

Arctic cyclones, true to their unpredictable nature, often form extremely fast. A cyclone can form in the polar regions in less than 24 hours, which contrasts with the cyclones of warmer latitudes, which require much longer to from. They move rapidly over the polar land and sea, bringing bitterly cold temperatures, massive amounts of snow which can produce white-outs that last for days, and extremely high winds.

These phenomena come in spiraling bands, just like the rain bands in a tropical hurricane in the Atlantic or a Pacific typhoon. These bands can strike with alarming speed, and can bring dangerous white-out conditions to the northern few northern towns that lie within the area affected by Arctic cyclones, such as those in northern Alaska or Siberia.

An Arctic cyclone can last for as short a time as several days, but the average duration of such a storm is 21 days, which is far longer than the typical cyclonic average of 3 days. The longest-lasting Arctic cyclones endure for about a month.

The effects of Arctic cyclones on other weather

Although they usually don't venture below the boundaries of the polar regions at 68 degrees north or south, Arctic cyclones are powerful storms that affect the weather conditions of the rest of the world through various indirect means. They alter ocean salinity and ocean levels, can cause or prevent coastal flooding far away depending on their frequency and strength, and many other subtle effects.

One of their most interesting effects is on middle-latitude cold in the winter. Since Arctic cyclones are low pressure areas, they tend to 'suck' air inwards towards them. Being such enormous lows, this indrawing of air has an immense reach. Strong cyclones in the winter will pull tropical air northwards, moderating temperatures, while flabby cyclones allow arctic air to move south, and result in bitterly icy cold spells.