VANCOUVER -- Environment Canada is warning of a heavy snowfall as a Pacific storm arrives in Southern B.C. this weekend, and traffic near the Coquihalla summit appears to be backed up as of Saturday morning.

“Significant amounts of snow are expected,” along the Coquihalla Highway between Merritt and Hope, reads a special weather warning released Saturday morning by the agency.

The Coquihalla, a section of Highway 5, is a major multi-lane highway connecting the Fraser Valley to the Okanagan, and passes over large mountains. It is notorious for difficult winter driving conditions.

Photos from highway webcams show snow on the roads and cars and trucks at a standstill around 11:30 a.m. heading southbound near Zopkios Rest Area, just below the Coquihalla summit.

“25 to 35 centimetres of snow is forecast from tonight through Sunday evening,” the statement continues.

Drivers are warned to expect “hazardous” conditions amid suddenly changing weather.

“Prepare for quickly changing and deteriorating travel conditions. Visibility may be suddenly reduced at times in heavy snow,” says Environment Canada.