Environment Canada is forecasting wind chills reaching -40 by Friday night and Saturday morning.
For the second time in recent weeks, the country's weather agency says those in the regions closest to the B.C.-Alberta border can brace for extremely cold temperatures.
They report that the overnight lows Friday will be between -22 and -28, but winds around 30 km/hr will bring that down to -35 to -40.
Wind chills are expected to improve a bit Saturday afternoon.
"Risks are greater for young children, older adults, people with chronic illnesses, people working or exercising outdoors, and those without proper shelter," says Environment Canada.
Mainroad East Kootenay is urging drivers to prepare for cold and windy conditions which may cause falling branches and other debris on the region's highways.