Environment Canada is warning that up to 15 centimetres of snow could accumulate in parts of Metro Vancouver by Thursday morning.

On Wednesday, the agency issued snowfalls warnings for Vancouver, New Westminster and the North Shore, saying that "a frontal system advancing from the Pacific" will result in up to five centimetres of snow on Wednesday.

"We'll likely see perhaps up to 10 centimetres total overnight tonight and into tomorrow morning before it switches over to rain later in the afternoon," said Environment Canada meteorologist Greg Pearce.

"If you look out the window tomorrow morning and see a real mess, then if you don't have to travel, don't travel tomorrow -- especially in the morning hours for Vancouver."

The City of Vancouver said it is preparing for the severe weather, with dozens of trucks out salting and brining.

"We do have a number of staff on 24/7, an increased level of staff on until 7 o'clock tonight and then all through the night as well," said Taryn Scollard, director of streets and engineering.

The snowfall warning also includes the Sea-to-Sky area between Squamish and Whistler.

The same frontal system has triggered a winter storm warning for inland communities such as Hope, Chilliwack, Langley, Surrey, Maple Ridge and Coquitlam, where up to 20 centimetres of snow is expected to accumulate.

"For the Fraser Valley, we're looking at snow developing tonight," Pearce said. "They could see a possibility of up to 10 to 20 centimetres in the valley before things switch over to freezing rain during the day (Thursday)."

Municipal crews say they're preparing for the worst case scenario—black ice forming overnight.

"We're going around the clock," said Langley Roads operations manager Brian Edey. "We scheduled trucks and drivers from now until tomorrow morning."

The preparations included lane closures on the Port Mann Bridge Wednesday so technicians could work on reloading snow collars and prevent ice bombs from falling.

The latest forecasts and weather warnings are available on Environment Canada's website.

With files from CTV Vancouver's Julie Nolin and Michele Brunoro