Classes cancelled and more shelter spaces opened, as snowfall warnings cover most of B.C.

Snowfall warnings are in place for more than two dozen regions in British Columbia, leading some post-secondary institutions to cancel in-person classes in anticipation of the weather.

After a week of record-setting cold temperatures due to Arctic air blowing across the province, Environment Canada says a Pacific low-pressure system is now about to replacethat, bringing with it widespread snow.

Around two-thirds of the province is covered by asnowfall warning, which says 10-20 centimetres will fall along the South Coast from Tuesday night into Wednesday morning. Depending on temperatures, the precipitation could also become freezing rain in some areas.

On Tuesday night, Vancouver Mayor Ken Sim announced that an extreme weather alert would remain in effect until Thursday, and more shelter spaces and warming centres were being opened in response to the forecast.

The city has also encouragedessential travel only on city roads and is reminding anyone who must drive to have winter tires on their vehicle and stick to priority routes.Drivers can use city traffic cameras to check road conditions.

Both the University of British Columbia and BCIT announced that all in-person classes arecancelled on Wednesday because of the forecast.

WATCH |What to expect from the latest round of snowfall:

Here's what B.C. can expect from latest round of snowfall

5 months ago

Duration 2:14

A low-pressure system will move across southern B.C. beginning Tuesday night. CBC News climate and science specialist Darius Mahdavi tells BC Today host Michelle Eliot what is expected to happen.

By midday Tuesday, snow was already falling further north, with expected accumulation ranging from upto 10 centimetres on the North Coast to 15 centimetres in Prince George.

"Visibility may be suddenly reduced at times in heavy snow," said Environment Canada on its website. "Surfaces such as highways, roads, walkways and parking lots may become difficult to navigate due to accumulating snow.Be prepared to adjust your driving with changing road conditions."

Along the South Coast temperatures are expected to be steady around 1 C Tuesday night before getting above zero for Wednesday. Rain is forecast for the rest of the week, with highs to 8 C by Saturday.

Elsewhere in B.C on Tuesday morning temperatures were still frigid, with Fort Nelson as the cold spot at 25 C and several other places in the northeast, central and southeast in the minus double digits, despite wind chill values easing.

For up-to-date road conditions around the province, visit DriveBC.ca.