The term is new to many people but the feature is not. The danger is Arctic air reaching places not used to it, so prepare for colder temperatures and keep emergency kits at home and in the car.
What it is
The polar vortex is a large area of low pressure and cold air surrounding both poles. "Vortex" refers to the counter-clockwise airflow that helps keep cold air near the poles. It is always there, weakening in summer and strengthening in winter.
Where it is
It is not a surface feature. Forecasters study it tens of thousands of feet up in the atmosphere.
How it links to cold outbreaks
In the Northern Hemisphere it often expands and sends cold air south with the jet stream. This happens fairly regularly in winter and is often linked to large outbreaks of Arctic air in the U.S. The NWS cites the January 2014 outbreak as similar to earlier outbreaks in 1977, 1982, 1985 and 1989, and says Europe and Asia have cold surges connected to it too.
The real hazard
The main hazard is how cold it gets when Arctic air moves into areas that are not usually that cold.
What to do
The NWS says there is no cause for alarm, but people should prepare for colder temperatures, check local forecasts and maintain emergency kits at home and in cars. See our guides on winter home preparation and on frostbite and hypothermia.
Check your own location
See current official alerts and the impact for your ZIP code.
Common questions
What is the polar vortex?
A large area of low pressure and cold air surrounding both of Earth's poles. The word vortex refers to the counter-clockwise airflow that helps keep cold air near the poles.
What was the strongest or worst polar vortex in history?
The National Weather Service does not rank them. It cites the January 2014 cold outbreak as similar to earlier outbreaks in 1977, 1982, 1985 and 1989.
Is the polar vortex new?
No. The National Weather Service says the term has only recently become popular, but the feature has always existed.
Does the polar vortex cause cold outbreaks?
In winter it often expands and sends cold air south with the jet stream, and this is often linked to large outbreaks of Arctic air in the U.S. The NWS cites the January 2014 outbreak as similar to earlier ones in 1977, 1982, 1985 and 1989.
Sources
Reviewed by the Storm Incoming editorial team on October 27, 2026. Follow local emergency officials if their instructions differ.