A two-motorcycle crash Wednesday at the intersection of S.D. Highway 16 and Promise Road left three riders with serious injuries, according to a Rapid City Police Department news release.

At about 8:30 a.m., a motorcycle driven by Andre McDonald, 49, of Quebec, Canada, was struck from behind by a motorcycle driven by Bruno Larose, 52, of Quebec, Canada, according to police. Both drivers were riding with several other Canadian motorcyclists. Lucie LaPointe, 48, also of Quebec, Canada, was a passenger on McDonald's motorcycle.

All three were transported to Rapid City Regional Hospital with injuries. McDonald and Larose was listed in critical condition and LaPointe was listed in serious condition. None of the riders was wearing a helmet.

The investigation indicates McDonald slowed near the intersection and Larose failed to slow. Larose's vehicle struck the trailer on the lead motorcycle, according to police. Both motorcycles left the road. The crash remains under investigation.

The Rapid City Police Department, Rapid City fire department and South Dakota Highway Patrol responded to the crash.