The first accident happened just before 1 p.m. when two cars collided head-on and a woman was airlifted to hospital with serious injuries.
The two officers were injured at about 4:15 p.m., on the same road, when their unmarked car collided with a pickup truck.
The oficers were also airlifted to hospital. Their injuries are serious but non-life-threatening, according to a news release from the force.
The driver of the truck was also injured and taken to hospital.
The province's Special Invesitgations Unit has been called in to investigate the accident between the police vehicle and the pickup.
Investigators say they will need more time before they can say if the weather was a factor in the original accident.
Two other people were injured in the head-on crash and rushed to hospital by ground ambulance.