A passenger on a motorcycle was injured after being struck by a falling rock Tuesday afternoon on Glacier National Park's Going-to-the-Sun Road.

The motorcycle with two people was traveling east on Sun Road near Triple Arches, west of Logan Pass, when the passenger was struck by a 10- to 15-pound rock at around 2:30 p.m.

The passenger was knocked unconscious for a short time, but radio dispatch reports indicated the victim was stable soon after the incident occurred.

The victim was transported by Three Rivers Ambulance to a lower section of Sun Road near the Red Rock Point area, where the ALERT helicopter from Kalispell was able to land.

The victim was flown to Kalispell Regional Medical Center, landing at about 4:45 p.m.

Responding park rangers reported that the passenger was wearing a helmet and that there were no other injuries involved with the incident, which will be investigated by the National Park Service.