Low over the Arctic Ocean
A low pressure system hovers in the center of this image of the Arctic Ocean. On the right (East) side of this image are the Queen Elizabeth Islands of Canada. The Arctic is the smallest ocean, covering an area of about 4 million square kilometers (5.4 million square miles). Low pressure systems in this region are often caused by the interaction of warm and cold air masses at the surface, which pushes air upwards into the atmosphere, where it cools and produces clouds. Polar lows are similar to tropical cyclones â€“ called hurricanes in the Caribbean and North Atlantic if they reach sufficient strength â€“ but are much shorter-lived, lasting only about 12 to 36 hours. They are responsible for high surface winds and snow, and sometimes act quite like hurricanes, losing strength as they pass over land and are separated from their source of heat energy. Polar lows are often easily recognizable in satellite images because of their characteristic pattern, sometimes called a “comma cloud” because of their hook-like shape.