A surprise snowstorm caused traffic delays around the Lower Mainland Sunday. (CBC)

Commuters trying to get back to school and work Monday morning will be forced to deal with the aftermath of Sunday evening's surprise snowstorm, and are being warned to expect delays and huge crowds if they use public transit.

TransLink said it plans to run longer SkyTrains for the Monday morning commute and will have each staffed by an attendant. Despite that, transit users are being told to be patient and dress for the elements.

"If you're taking the bus, don't be surprised if your bus gets terminated before its usual ending point, and you have to get off and walk at some point," said Drew Snider of TransLink.

Schools were closed to many students in the Fraser Valley area Monday, including all public schools in Abbotsford, Maple Ridge and Pitt Meadows. The University of Fraser Valley was also closed Monday.

In Langley, Dorothy Peacock and Glenwood elementary schools were closed because of power outages, but all other schools were open. Lions Bay Primary School in West Vancouver was also closed because of a power outage.

On Vancouver Island, all public schools were closed in the Cowichan Valley, Nanaimo-Ladysmith and the Alberni Valley.

Although most Vancouver schools were open, Montessori schools were closed.

In Surrey, Anniedale, M.B. Sanford, North Ridge and Panorama Park elementary schools, as well as Mountainview Montessori Elementary and Johnston Heights Secondary were closed.

Buses servicing special needs students in Surrey and Delta were also unavailable due to road conditions.

Simon Fraser University's Burnaby campus was also closed for the first day of school Monday.

The weekend snowfall pounded the South Coast on Sunday evening and caused traffic mishaps around the Lower Mainland.

Travel is not being recommended on Highway 99 from Whistler north through Pemberton because of heavy snow.

Power was also cut for about 5,000 customers in the Mission-Abbotsford area, according to BC Hydro.

Skiers, snowboarders stranded

On Sunday night, skiers and snowboarders on Grouse Mountain in North Vancouver were stranded as a bus carrying 60 passengers slid in a snowbank and ended up stuck close to a cliff.

Transit officials and the North Vancouver fire department were called to free the bus by pouring salt on the front and rear tires of the bus.

The bus was freed in about 30 minutes, but not before dozens of skiers and snowboarders were forced to hike down the mountain on Capilano Road.

"It's been bad all over and [the snow] hit so quickly and it come in with much more intensity than anyone expected, really," said Snider.

TransLink is reminding customers to expect spot closures and detours in regularly snowed-out routes, such as in:

• Coquitlam's Westwood Plateau area.
• Mathers Avenue in West Vancouver.
• 23rd Street in North Vancouver.
• Anything above the Upper Levels Highway.