A portion of Ontario’s Highway 11 has been closed in both directions after a large “very serious” crash involving multiple vehicles in snowy, wintery conditions, officials say.

Ontario Provincial Police said the highway and other back roads located near Orillia, Ont., was closed on Friday after the multi-vehicle collision, as emergency services begged for space to respond to the incident.

Specifically, Highway 11 was closed northbound from Highway 400 to Coldwater Road and southbound from County Road 169 to Line 15.

In addition, OPP said Line 15 North is closed from Highway 11 to Old Barrie Road; Old Barrie Road is closed from Line 15 North to Memorial Avenue; Memorial Avenue is closed from Highway 12 to Highway 11; and University Road is closed from Old Barrie Road to Diana Drive.

Acting Sgt. Jake Daynes called the incident “very serious” and asked the public to avoid all unnecessary travel on the roadways where visibility and road conditions are poor.

Daynes also advised that anyone involved in a collision should remain in their vehicle.

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“Do not get out of your vehicle because you could potentially get injured from other oncoming motorists due to poor visibility conditions,” Daynes said.

The force is promising a live update on details from the crash at 2 p.m. on X.

Daynes said a warming centre has opened at 100 University Avenue in Orillia.

The area was under a snow squall warning on Friday morning, with another five to 20 cm of snow expected. Environment Canada warned of poor visibility from snow and local blowing snow.

OPP couldn’t immediately offer details of the collision but images from the scene showed a stretch of the snowy road with several crashed vehicles on the side of the roadway.

Officers asked people to avoid the area to limit similar crashes on other nearby roads after the highway closure.

“Side roads are experiencing higher volumes with similar road conditions resulting in subsequent collisions,” OPP said.

Ornge air ambulance told Global News it was requested to assist for reports of “a multi-vehicle pileup.” Two critical care land ambulances and two helicopters were assigned to responded to the scene but “were cancelled and have not completed any transports at this time.”

Parts of Highway 11 have already been closed for a major snowstorm this season.

The highway was closed between Huntsville and Orillia in late November after snow made it impassable.

Snowmobile-riding first responders took to otherwise impassable roads to help rescue people from stranded vehicles around Muskoka, police said at the time.

The storm was so severe that nearby Gravenhurst declared a state of emergency.