Arctic air over Western Canada has sent temperatures plunging. What you need to know about the polar vortex

If the frigid temperatures across British Columbiahave you feeling like you're in theArctic, your instincts aren't all wrong.

The polar vortex bringing freezing conditions to parts of the province originates in theNorth Pole meaningthat freezing air you're feeling on your face is quite literally from theArctic.

Here's what you need to know about the weather phenomenon.

What is the polar vortex?

The polar vortexes are large areas of low pressure and cold airhigh in the atmospherethat constantly swirlaround both theNorth Poleand South Pole.

Closer to the surface, thesevortexesare surrounded by thepolar jet streamsrelativelynarrow,rapidstreams of wind in the upper atmosphere that encircle the poles and usually keep cold air trapped.

But every couple of yearsthe polar vortex is disrupted, splitting into multiple "lobes" that extend south. That disruptionalso causes the polar jet stream to weaken, which can help push and hold the freezing air over parts of Canada and the US.

"What we're experiencing right now and what happens a couple of times a winter,is when that vortex weakens a little bit," saidJuneSkeeter, a postdoctoral fellow in geography atthe University of British Columbia.

"You can think of it as holding the cold air in, and when it weakensa little bit the cold air can kind of move out of where it normally is."

Right now,apolar vortex lobeis sitting over much of B.C. andthe Prairies, bringing colder-than-usual temperatures.

What is the difference between the polar vortex and Arctic outflow?

Environment Canada also issued an Arctic outflow warning for much of British Columbia's coast.

While polar vortexrefers to thelarge system of cold airsittinghighover the region,Arcticoutflow refers to the surface-level winds now passing over the coast.

The outflow is described bySkeeteras "very cold air from the Arctic that has moved its way down here, and is kind ofparked on top of B.C. and Alberta. We call it an outflow warning because cold air is very heavy and dense, and so it wants to sink. It flows kind of the same way water might and sinks down."

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Why is Western Canada so c-c-cold right now?

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Duration 3:25

CBC News Science and Climate Specialist Darius Mahdavi explains the global climatic systems that are causing such a cold snap in British Columbia and the Prairies.

DariusMahdavi,CBC'sscience and climate specialist,explains the winds are whipped up because "Arcticair wants to make it out to the Pacific. This can cause winds blowing 60 to 80 kilometres per hour, which is why the wind chill is such a problem for the coast."

Why isthepolar vortex disrupted?

Even though the polar vortex is strongest in winter, it can be disrupted by certain patterns in the upper atmosphere. According to the U.S. National Oceanic and Atmospheric Administration, those patterns can becomemore common in late winter during El Nio years.

La Niaand El Nioare two opposing climatepatterns that affect winters in Western Canada. This winter has seen anEl Nioweather pattern, bringing generally warmer, milder conditions throughout December and early January.

This is partly because El Nio usually causes the polar jet stream to shift further north, locking away more of that Arctic air. But thanks to waves generated in the upper atmosphere, ElNiocan also disrupt the polar vortex. That, in turn, can cause the jet stream to become more wavy, pushing Arctic air further south.

Skeeter said weather is "quite random and chaotic," making it difficult to draw direct links between broad weather events.

"But speaking in general terms, strong contrast between the ocean and land temperatures is one of the things that can cause the jet stream to weaken," they said.

The cold weather is expected to continue in B.C. for much of the weekend, with temperatures only rising to 6 C in Vancouver on Saturday.

Environment Canada said the wind chill will likely ease Saturday afternoon but it could still make it feel like10 C to 20 C through Sunday morning in Metro Vancouver.