Police are citing wintry weather conditions in three crashes Sunday that left four people dead.

A 53-year-old man died after losing control of his pick-up truck and veering into the path of a car on Highway 63 Sunday afternoon.

Around 12:30 p.m. the southbound pickup veered sideways into the northbound car near House River.

The driver of the pickup died at the scene while the driver of the car was air lifted to hospital with life-threatening injuries.

Police believe weather conditions contributed to the crash, one of three fatal collisions in northern Alberta yesterday.

A crash involving a semi-trailer on Highway 881 near Conklin killed one person while two people died in a collision involving a mini-van and an SUV, just south of Villeneuve, northwest of Edmonton.