A polynya is a Russian term for any non-linear-shaped area of open water within the ice pack. Polynyas may contain brash ice and/or be covered with new ice, nilas or young ice; submariners refer to these as skylights. Sometimes the polynya is limited on one side by the coast and is called a shore polynya or by fast ice and is called a flaw polynya. If it recurs in the same position every year, e.g., off the mouths of big rivers or glaciers, it is called a recurring polynya. A temporary small clearing in pack ice which consists of small floes and brash in continuous local movement is called an unstable polynya; an opening which is flanked by large floes and therefore appears to be relatively stable is called a stable polynya. Polynyas range in size from relatively small to enormous. The largest polynya observed in the Antarctic was the Weddell Polynya of 1975-77, covering an area of 2x105km2.
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