The highway has since been re-opened.
The Saskatchewan RCMP released a notice that they and other first responders are currently on the scene of a serious collision on Highway 1 at Kalium Road between Moose Jaw and Belle Plaine.
The westbound lanes are currently restricted and being controlled by the RCMP.
Drivers are asked to please follow any directions of police on the scene.
Eastbound travel is open, but motorists must slow down to ensure the safety of emergency responders.