Teen in critical condition following highway crash in Brooks, Alta.

A Stars Air Ambulance in a file photo.

A teen was airlifted to hospital in Calgary in critical condition following a highway crash in Brooks, Alta., on Monday afternoon.

According to the RCMP, the collision occurred between a pickup and a semi-tractor trailer shortly after 2 p.m., at highways 1 and 873.

There were four people in the pickup, including two 15-year-old boys and a 41-year-old woman.

Mounties said one person was taken to hospital in Brooks by EMS and then to Calgary by air ambulance.

STARS confirmed the flight and that the teen patient's condition was critical.

Two others were not significantly injured, RCMP said.

No information was available about the fourth person in the pickup.

The semi had one occupant. No information was available about them, either.

According to police, initial investigation shows the pickup made an unsafe left turn and was struck by the semi.

The scene was clear by Monday evening.