A 33-year-old man is dead and his wife seriously injured after their vehicle rolled down a hillside in Flathead National Forest.

According to Montana Highway Patrol trooper Patrick Herman, the man was driving a Subaru Outback southbound on Spotted Bear Road. The driver reportedly attempted to negotiate a curve and applied the brakes 100 feet before a cliff, when the vehicle went off the dirt road and rolled down the hillside until it came rest on its roof. Troopers were dispatched to the scene at 1:47 a.m. Sunday.

The passenger, a 29-year-old woman, was transported by ambulance to Kalispell Regional Medical Center. The couple is from Galloway, New Jersey.

The driver and passenger weren’t wearing seat belts according to Herman. The crash remains under investigation, but alcohol and speed are suspected factors he said. Road conditions were dry.

The man’s name was not released as of presstime.