Baby, it's cold outside! Arctic air sends temperatures plunging across B.C.

Much of B.C. will remain in the grips of a cold snap this week as a blast of Arctic air pushes temperatures 10 to 20 degrees below seasonal norms.

Metro Vancouver could drop as low as –9 C by Thursday night, while Prince George could drop to –28 C.

Environment Canada meteorologist Matt MacDonald said a particularly strong high pressure ridge of Arctic air sitting over the B.C.-Yukon border is bringing a range of weather to different parts of the province.

"We typically see these one to four times per winter, but this one is quite strong and is lasting quite a while," said MacDonald.

"That cold, heavy air flows out toward the coast and comes screaming out all the inlets and fiords," said MacDonald, and that's triggered outflow warnings for several coastal areas.

In Whistler wind chill values of –20 can be expected today, while for the Chilcotin and inland sections of the north and central coasts wind chill values will drop below –40 and will continue throughout the week.

Wind chill a factor

But in the interior the effect is different.

"Anytime we have a ridge of high pressure in place, winds [in the interior] are very light and the atmosphere is very stable and there is not much mixing happening down near the surface of the earth," says MacDonald.

That's triggered an air quality advisory for parts of the Central Interior, including the Bulkley Valley, Prince George and Yellowhead, which is expected to persist until Thursday.

"We are going to be in the deep freeze another five days, up until Saturday, and then we will get into our good, old storm track from the Pacific," he said

That will bring rain for the South Coast by the weekend and flurries for the interior as temperatures rise closer to normal.

Don't blame La Nina

MacDonald says while there is still a weak La Nina in place in the Pacific Ocean, it's only partly responsible for the recent snow and cold.

"I think La Nina is helping to load the cards in favour of these snowy and cooler conditions conditions, but it is not solely responsible," he said.

"Really it is just variability in the jet stream ... These ridges of high pressure that form over the Arctic, we always see them every year."

While the ridge is expected to break down later this week, MacDonald says temperatures might stay cool enough to keep some of the snow around until Christmas.

"I would estimate a 40 to 50 per cent chance right now for a white Christmas," he said.

Snow clearing budgets blown

Meanwhile, all the recent snow has forced several Vancouver Island communities to burn through much of their snow clearing budgets already.

After just three snowfalls, the City of Victoria has ploughed through its annual snow clearing budget of just $36,000.

In neighbouring Saanich one quarter of the snow budget is used up, and in Nanaimo half of their $500,000 budget has already been spent.