What Is an Arctic Outbreak?
An Arctic outbreak occurs when a large mass of very cold air moves south from the Arctic into lower latitudes. It can cause temperatures to fall sharply across a large area and remain unusually cold for several days.
Arctic outbreaks are responsible for some of the coldest weather experienced across Canada. Depending on the strength of the outbreak, temperatures can fall well below seasonal averages and dangerous wind chills can develop.
These events can affect large parts of the country at the same time. The cold air can also interact with lakes and passing weather systems, contributing to additional winter weather such as heavy snow and snow squalls.
Related Conditions
| Condition | Description |
|---|---|
| Extreme Cold | A period of dangerously low temperatures that can pose risks to people, animals and infrastructure. |
| Polar Vortex | A large area of low pressure and cold air that normally circulates around the polar regions. |
| Arctic Air Mass | A large body of extremely cold air that develops over Arctic and polar regions. |
| Cold Front | The leading edge of an advancing mass of colder air that can cause temperatures to fall quickly. |
| Deep Freeze | An extended period of temperatures remaining well below freezing. |
Related Alerts
| Alert | Description |
|---|---|
| Extreme Cold Warning | Warns when very cold temperatures or wind chill create dangerous conditions. |
| Wind Warning | Issued when strong winds are expected to reach warning criteria and create hazardous conditions. |
| Snow Squall Warning | Warns of snow squalls that can cause sudden poor visibility and hazardous travel. |
| Blizzard Warning | Warns of strong winds and severely reduced visibility in snow or blowing snow. |
| Winter Storm Warning | Warns of a significant combination of hazardous winter weather. |
What Causes an Arctic Outbreak?
Arctic outbreaks occur when atmospheric patterns allow extremely cold air from northern Canada and the Arctic to move much farther south than usual.
Very cold air is normally concentrated in northern regions, but large-scale changes in the atmosphere can allow some of this air to spill southward. Strong areas of high and low pressure help determine where the cold air travels and how far south it reaches.
The polar vortex can also play a role. The polar vortex is a broad circulation of cold air high in the atmosphere around the polar regions. Changes in this circulation can sometimes contribute to patterns that allow Arctic air to move farther south.
As an Arctic air mass arrives, temperatures can fall rapidly and remain well below normal. Strong winds can make conditions feel even colder by increasing wind chill, sometimes creating extreme cold conditions.
Arctic outbreaks can also influence other types of winter weather. When very cold air moves across the relatively warmer waters of the Great Lakes, for example, it can help create lake-effect snow and snow squalls downwind.
The severity and duration of an Arctic outbreak depend on the strength of the cold air mass and the larger atmospheric pattern controlling its movement.
FAQ
There is no single temperature that defines every Arctic outbreak. Temperatures depend on the strength of the air mass, location and time of year, but they can fall well below seasonal averages.
An Arctic outbreak can last several days or longer depending on how quickly the atmospheric pattern changes and warmer air returns.
A cold snap is a relatively short period of unusually cold weather. An Arctic outbreak specifically involves a large mass of Arctic air moving south and can affect a much larger region.
No. The polar vortex is a large circulation of cold air around the polar regions. An Arctic outbreak occurs when very cold Arctic air moves south into lower latitudes.
Yes. Arctic air can interact with moisture and weather systems to produce snow. Cold air moving across the Great Lakes can also contribute to lake-effect snow and snow squalls.
The cold air originates in high-latitude Arctic and northern regions where very low temperatures allow large masses of cold, dense air to develop.