Police are investigating after a Wednesday evening crash southeast of Calgary that sent three people to the hospital.

At approximately 9 p.m. on October 3, emergency crews were called to the scene of an accident involving two semi tractor-trailer units.

The accident occurred on Highway 791 near Highway 22x. Three men were transported to the hospital.  One man was in stable condition however the other two men were transported in life-threatening condition.

The crash did affect traffic for several hours as police continued to investigate and debris was removed from the scene.  

Police have not released the cause of the accident and it remains under investigation.  Police say the heavy snowfall over the past couple of days did create extreme conditions on the highway.