Three people are dead after two vehicles collided head-on in Pickering this afternoon, Ontario Provincial Police confirm.

Police were called to the scene of the crash on Highway 7 between Sideline 26 and Sideline 28, near North Road, at around 12:10 p.m.

According to OPP Sgt. Dean Korn, an eastbound Mercedes struck a westbound BMW while trying to pass another vehicle on the highway.

The impact of the crash threw both vehicles off the roadway and into a ditch.

Three people travelling in the BMW were killed in the collision. OPP say all three victims are from the GTA but provided no other details on their identities.

A fourth person was transported to Markham Stouffville Hospital via Ornge Air Ambulance and later transported to a Toronto-area trauma centre. According to a spokesperson at Ornge, the victim is a woman in her 20s who had suffered serious upper body injuries.

Korn said the male driver of the Mercedes suffered minor injuries and was taken to local hospital for treatment where he’s “expected to make a full recovery.”

A Durham Region Transit bus was called to the scene for police investigators to use as a warming station, as much of southern Ontario is under an extreme cold weather alert. Environment Canada was calling for a high of -17 C in the GTA, feeling more like -32 when the wind chill is factored in.

On top of the blistering conditions, Korn said snow had blown across from the nearby open fields and covered the roadway where the crash occurred creating “slippery conditions in that particular area.”

He said it’s possible weather conditions played a role in the crash but that driver error is more likely.

“Speed does not appear to be a factor, nor does alcohol or any other illegal substance. This just appears to be a poor decision by someone who passed when they shouldn’t in an unsafe spot,” he said.

While crews have started to comb through the wreckage, Korn said the frigid weather is also hampering some equipment needed to complete the extrication process.

Police closed Highway 7 between Brock Road and York Durham Line for several hours while traffic services investigated. The highway reopened shortly before 5:30 p.m.