An arctic outflow that's rolling into B.C. this week is expected to deliver bitterly cold temperatures to the South Coast, posing a real threat to people who are living on the streets.

The wintery weather has triggered several warnings around the province, including in Whistler, Howe Sound and the Fraser Valley, where wind chill values of -20C are expected overnight.

“If outside, dress warmly in layers and stay dry. Cover as much exposed skin as possible to avoid frostbite,” Environment Canada said in an alert.

Vancouver's forecast is less extreme, with overnight temperatures ranging from -5C to -9C over the coming days, but it's still more than enough to raise serious concerns for the city's homeless population.

"It's dangerous for people out there, there's no question about it," said Jeremy Hunka of the Union Gospel Mission. "We're going to do what we can to either get them inside or to give them what they need to survive."

UGM is one of several shelters around Metro Vancouver that have added extra emergency beds to offer more people a warm place to sleep.

To help those who still end up spending their nights outside in the cold, the charity has been asking people to donate gently used winter clothing, particularly waterproof jackets and boots.

"We have been selectively handing out survival gear to different people who are living on the fringes of society for several weeks," Hunka said.

"Heat reflective blankets, heat reflective tarps, things like sleeping bags, waterproof jackets and waterproof boots, those things can potentially save a life, especially with the really extreme cold temperatures that we're about to get."

The weather forecast could potentially mean more hazards for Lower Mainland drivers as well. Though most of the roads have been cleared since the weekend's snowstorms, police still urge motorists to be wary of black ice.

TransLink said staff will be using a de-icing spray on overhead trolley wires for buses and on SkyTrain tracks in an effort to keep the system running smoothly during the cold snap.

To learn more about donating clothes to Union Gospel Mission, or to make a monetary donation, visit the charity's website. 

With a report from CTV Vancouver's Ben Miljure