One car struck a tractor trailer on a curve and then a second car was hit by the truck as it swerved into the opposite lane.
The drivers of both cars died in the collision and a passenger in the second vehicle suffered minor injuries.
The truck driver was also taken to hospital with minor injures.
Wreckage from the impact was spread along the highway from the heavily damaged vehicles.
Provincial police spokeswoman Joyce Kemp said a police team of collision specialists was at the scene to determine what happened.
She said it's not clear why the first car lost control on the curve.