Polar Vortex

The polar vortex is a large area of low pressure and cold air surrounding Earth's poles, existing year-round but strengthening in winter. It is bounded by a band of swirling jet stream winds. Occasionally, this vortex weakens and becomes distorted, sending frigid Arctic air plunging south into mid-latitudes, causing severe winter outbreaks. While a natural phenomenon, its increasing instability may be influenced by climate change and Arctic amplification.