A large, powerful high pressure system originating in the Eastern or Western Pacific and stretching to the North Pole is required to displace the pocket of cold air. "These high pressure systems can reach Alaska, but it is not typical to stretch all the way to the North Pole," according to AccuWeather.com Senior Meteorologist Brett Anderson. The vortex is capable of delivering subzero temperatures to the United States and Canada for several days at a time. When the strong air from the Eastern or Western Pacific weakens and falls apart, the polar vortex will retreat into place near the North Pole.
