One person suffered life-threatening injuries after a multi-vehicle collision in the northbound lanes of Highway 400 on Tuesday morning.
Police say the crash happened near Teston Road at approximately 4 a.m. before the heavy snow started to fall in the area.
OPP officers say an SUV stalled in the left lane and was struck by two other vehicles.
The driver of a Jeep was rushed to Sunnybrook Hospital.
The highway was closed for several hours for the investigation.
It reopened shortly after 10 a.m.