A 21-year-old man was killed Saturday when a van was rear-ended by another vehicle along the side of a road in northeast Calgary.

Police say the man and his mother arrived at the scene in a Dodge Caravan to help his father, who had lost control of the car, which flipped and ended up in a ditch.

While the son was standing at the back of the van with the hatch open, he was hit by an approaching Ford F250.

Police say slippery road conditions and alcohol were factors in the crash, which sparked a chain reaction of collisions.

Charges are pending against the 28-year-old driver of the F250, police say.

The accident occurred around 7 a.m. The name and hometown of the young man who died was not immediately available.

Another man injured in one of the other collisions was taken to hospital with a chest injury.