Transit riders were ordered off buses and multi-car crashes were reported across Vancouver as the city's mayor promised crews were out in "full force" as the region struggled under a snowfall warning.

As much as 15 centimetres of snow was forecast to hit B.C.'s South Coast by Saturday, and heavy snow began falling early Friday.

Crews started brining and salting main roads in Vancouver four or five days ago in anticipation of this snowfall, said the city's head of engineering, Jerry Dobrovolny.

Dobrovolny said 40 pieces of equipment were working to clear arterial roadways, including bus and truck routes and major thoroughfares. Crews have also been redeployed to clear sidewalks around bus stops, he added.

Acknowledging the weather-related transit and driving slowdowns happening across the city, Dobrovolny advised residents to get off the roads if at all possible, and leave work early.

"There is another wave of snow expected to come in later in the day and so I think it would make sense if people are able to leave early and avoid the evening rush hour so that they're not caught in traffic at the same time that heavy wave of snow comes, currently forecast to be around 6 p.m." he told reporters at a briefing alongside Mayor Gregor Robertson.

People experiencing snow and ice problems were urged to call 311.

Transit started experiencing slowdowns and problems early in the day as the white stuff started sticking on the roads.

TransLink said it was experiencing "significant delays" on multiple routes all across the system.

"We work closely with our municipal partners to ensure all bus routes are plowed first, however multiple bus routes are currently impacted due to road conditions," senior media relations advisor Chris Bryan wrote in a bulletin sent to CTV.

Six buses that serve North Vancouver were being detoured at upper elevations, and all West Vancouver Blue Bus service was being routed down Marine Drive.

Before dawn, TransLink announced bus service heading up Burnaby Mountain to the SFU campus was suspended over the icy conditions. The university announced it would cancel afternoon classes over increasing concerns over weather and road conditions.

The 99B-Line, the main route connecting Commercial Drive SkyTrain to UBC, was experiencing widespread delays.

Buses were sliding and skidding out on the route on Broadway near MacDonald Street, and struggling up the hill near the Fraser Street stop.

Riders were ordered to get off a B-Line bus that couldn't navigate the hill, and it was unclear when another bus could collect them to finish the journey.

In downtown Vancouver, at least six buses were pulled off to the side of Robson Street after experiencing issues navigating the hill incline.

Drivers experienced weather-related slowdowns across Vancouver and the North Shore. A Google traffic snapshot at 9 a.m. showed congestion on virtually all major routes.

On East 29th Avenue near Nanaimo Street, video posted to Twitter showed a multi-car collision on the residential side street. A Vancouver police officer could be seen sliding down the unplowed road, apparently not able to get traction.

In the steep slopes of Fairview, at least four vehicles collided near the intersection of West 8th Avenue and Willow Street.

On Oak Street, a major thoroughfare, a CTV reporter was forced to abandon her vehicle at the side of the road because it was too slippery.

The city urged people to keep their sidewalks and driveways clear of snow, and shovel snow as soon as it falls to avoid freezing and ice buildup.

Garbage and recycling pickup could be delayed if snow accumulates in residential side streets and lanes, it warned, saying people should leave our their garbage and recycling bins and crews would be out "as soon as possible."

More on Environment Canada's public weather alerts for British Columbia

More to come…