Incoming Arctic air means it's going to be a cold week across B.C.

Environment Canada is warning of extreme cold across swaths of northern B.C. while more snow is expected in the southern Interior, as Arctic air moves across the province.

The weather agency says the cold air will settle in Monday and persist for the rest of the week after a fairly mild winter so far. It says temperatures in the Interior will be 10 to 20 C below the seasonal average, while coastal areas including Metro Vancouver will be 5 to 10 C below seasonal norms.

Extreme cold warnings are in place for the Peace River, Bulkley Valley, Stuart Nechako, Prince George, Cassiar Mountains, Fort Nelson, Watson Lake and Williston areas, as well as Yoho and Kootenay national parks. 

In those regions, overnight lows combined with occasional winds could produce extreme cold wind chill values of near -40 to -45 C. 

Fend off frostbite

In Dease Lake, where an extreme cold warning is also in place, temperatures near –35 C combined with wind chill could bring the cold down to –50 C.

Residents are reminded to cover up as frostbite can develop within minutes on exposed skin under such frigid conditions.

Another warning covers the North Coast, where Environment Canada says cold temperatures combined with winds up to 50 km/h will create wind chills of –20 C or lower.

The Arctic air is moving toward the southern interior and will approach the south coast later Monday, the agency says. On Tuesday, temperatures are expected to keep falling as more Arctic air is forced southward.  

Strong outflow winds and brisk wind chill values are expected over southern coastal areas from Tuesday night. As a result, Environment Canada has also issued an Arctic outflow warning for Metro Vancouver. 

Seek shelter

According to CBC meteorologist Johanna Wagstaffe, temperatures in Metro Vancouver could drop down to –6 C overnight.

The region saw sudden flurries Monday afternoon. 

Wagstaffe said the snowfall was the result of a convergence zone across the region as outflow winds from the approaching Arctic front met the ocean.

"That created lift and isolated snow, as well as cumulus clouds," she said. "The whole event was sort of like pop-up thunderstorms but with snow."

Wagstaffe said the conditions shouldn't stick around for too long.

B.C. Housing says shelter access is being expanded across Metro Vancouver and anyone sleeping outside is encouraged to come indoors.

Calling the conditions "dangerously cold," spokesperson Sara Goldvine said 92 extreme weather shelter spaces will be open in the Lower Mainland in addition to the 282 shelter spaces that are already open every night.

People can phone 211 for free anytime day or night to find out where a shelter space is available in Metro Vancouver or Greater Victoria.

Click here for B.C. Housing's shelter list, which includes locations throughout the province.

Vancouver opens warming centres

In Vancouver, the city is opening 100 extra shelter spaces under the provincial extreme weather response shelter program, along with five emergency warming centres:

• Creekside Community Centre, 1 Athletes Way.
• Vancouver Aquatic Centre, 1050 Beach Ave.
• 1648 East First Ave, operated by Britannia Community Centre.
• Powell Street Getaway, operated by Lookout Society, 528 Powell St.
• Vancouver Odd Fellows Hall, 1443 West 8th Ave.

Andrea Jung, City of Vancouver social planner in the homelessness service department, said the warming centres open when the weather is forecast to be -5 C or below.

"They are able to accommodate anyone who wants to come inside out of the cold with pets, carts, bikes and belongings — all are welcome to come in and no reservations are required," she said.

Additional information like hours of operation can be found by phoning 311, she said. 

Warming centres are not set up with beds or mats, but do provide a safe and warm space for people living outside.

An overview of Vancouver's shelter and winter response strategy can be found here.

Freezing temperatures can be dangerous for those experiencing homelessness, and not everyone will want to or be able to access shelter this week, said Jeremy Hunka, a spokesperson for Union Gospel Mission in Vancouver.

Volunteers with the charity will be handing out essentials like waterproof jackets and sleeping bags this week, he said.

People looking to help out can do so by donating to a charity that's working to keep people warm and safe, he added.

"Unfortunately, we know that the need is really outstripping our response," Hunka said.

"The simple matter of fact is that hundreds of people will likely be outside during the cold snap this week."