The RCMP are investigating a three vehicle crash on Highway 39 just north of Estevan.
Police say a semi trailer rear-ended a truck, which in turn crashed into a car, Sunday at about 8:40 a.m. CST.
Two people in the truck were rushed to hospital with non-life threatening injuries.
The two people in the car and the driver of the semi were not hurt in the collision.
Police say road conditions are considered to be a factor - visibility was down to zero at the time of the crash.
Highway 39 just north of the Estevan weigh scales was blocked for part of Sunday morning, but it has since been reopened.
The RCMP are asking drivers not to travel until highway and weather conditions improve.
For the latest updates on road conditions people can check the provincial Highway Hotline.