Highway 2 north of Calgary has reopened after several multi-vehicle crashes left 40 people stranded earlier Saturday, according to Alberta Transportation's 511 road report service.

The road — a main artery for travellers heading north from Calgary — closed after four crashes near Crossfield involving about 30 vehicles. Those stranded by the accident were transported by bus to a nearby church to stay warm.

On Highway 2 northbound at Highway 72, there was a 20 vehicle pile-up involving one semi truck. Minor injuries were reported at this scene.

At Highway 2 southbound at Highway 73, 15 vehicles were involved in a crash including three semi trucks. Minor injuries were reported at this scene.

One man was sent to hospital with serious but non-life threatening injuries after a four-vehicle crash involving one semi truck on Highway 2 southbound near the Dickson Stevenson rest stop.

Another man is in hospital with life threatening injuries after a four-vehicle crash involving three semi trucks and a car at Highway 2 southbound at the Acme overpass. The man was in the car and the two other vehicle passengers were also taken to hospital but their conditions have not been confirmed.

Calgary and the surrounding area are currently under a snowfall warning, with temperatures hovering around -11 C with blowing snow. 

RCMP have issued multiple warnings about blowing snow and slippery roads making for dangerous driving conditions. 

People are being advised to avoid travel on highways in the area and to exercise extreme caution if they must drive.