Two people are in hospital after a crash along Highway 2, south of Bowden, Alta., Saturday afternoon.
RCMP said a blue SUV sideswiped a transport truck in the southbound lanes of the highway shortly before noon, lost control and rolled several times before coming to rest in the median.
A 50-year-old man from Innisfail, Alta., who was driving the SUV, suffered serious life-threatening injuries and was transported to hospital by STARS air ambulance.
A passenger was taken to hospital by ground with serious but non-life-threatening injuries.
"The collision forced the closure of the southbound lanes of the highway for approximately one hour while crews investigated," said Const. Steve Molnar of the Innisfail Integrated Traffic Unit, adding the highway has since been reopened.
Police say some southbound drivers caught in the traffic jam caused by the crash turned around and began driving north in the southbound lanes which posed an unnecessary danger to other motorists.
RCMP are trying to find out why the crash happened but say alcohol was not a factor.
Bowden is approximately 105 kilometres north of Calgary.