Freezing rain and a fresh dump of snow caused several vehicles to slide off the road in the Fraser Valley Thursday, including a semi-truck that flipped over on Highway 1.

Environment Canada issued new winter storm warnings as a strong Pacific frontal system moved into the region. Some areas, the agency warned, would be hit with as much as 15 centimetres of snow.

As the snow gave way to freezing rain later in the day, officials urged drivers to avoid the treacherous conditions if possible.

"Unless you really have to go out and be somewhere, stay home," Upper Fraser Valley RCMP Cpl. Mike Rail said. "Don't travel unless it's absolutely necessary."

In Abbotsford, a family of four was lucky to escape without injuries after their vehicle hit black ice and rolled over.

"(The) vehicle went off into the ditch," said tow truck driver Dan Popadynetz. "I flipped it over and pulled it out of the ditch."

Dangerous conditions are expected to persist through much of the region, from Hope right through to Abbotsford, which already had reports of freezing rain starting Wednesday night.

The wintry weather also led to some flight delays at the Abbotsford airport Thursday and caused headaches for homeowners who were forced to scrape the ice off their driveways and vehicles.

A separate snowfall warning has been issued for some of the Fraser Valley's highways, which are forecast to see up to 30 centimetres of fresh snow by the end of the day Thursday.

Affected routes include the Coquihalla Highway from Hope to Merritt, and Highway 3 from Hope to Princeton.

“Consider postponing non-essential travel until conditions improve," Environment Canada warned. "Visibility may be suddenly reduced at times in heavy snow. If visibility is reduced while driving, turn on your lights and maintain a safe following distance."

Meanwhile, a handful of winter storm warnings that were issued this week for parts of Metro Vancouver have ended.

That route could see up to 25 centimetres of snow by the evening, according to forecasters.

Other parts of B.C.’s South Coast were also facing severe winter weather. Snowfall warnings were issued this week for the Sea-to-Sky region between West Vancouver and Squamish as well as the Howe Sound area, where up to 30 centimetres of snow accumulated Wednesday night.

An additional five to 10 centimetres was expected on Thursday.

For the latest weather warnings and alerts from Environment Canada, visit the agency's website.

With files from CTV Vancouver’s Michele Brunoro