Just before 6 p.m. Sunday night, Smithers RCMP responded to a single vehicle crash on Highway 16 near Stenman Road about 10 kilometres west of Smithers.
BC Ambulance and Smithers Fire and Rescue had been advised and were already enroute.
RCMP said initial investigation revealed a car with two occupants was traveling southbound on Highway 16 when it suddenly swerved to the right, went off the road, hitting the ditch and rolling before coming to rest on the driver's side.
The car ended up facing the opposite direction in the southbound ditch.
A 41-year-old female was ejected from the vehicle on impact and transported to Bulkley Valley District Hospital by BC Ambulance.
She was flown out a short time later for further medical treatment, in stable but critical condition.
A 44-year-old male on scene was identified as the driver.
The male was also transported to the hospital by ambulance for non-life threatening injuries and later released.
Wildlife may have been a contributing factor in this incident.
Traffic was routed around the scene for about 30 minutes as the woman was carried carefully into a waiting ambulance.
Smithers RCMP would like to remind the public of the importance of wearing seatbelts, not only because it is the law, but because seatbelts do save lives.