A big rig that crashed in the California backcountry was seen dangling precariously over a river in the Friday after flipping on its side.

The semi was involved in a single-vehicle crash around 10:45 a.m. on Interstate 80 near Floriston in Nevada County, the California Highway Patrol told KTLA.

The driver suffered major injuries and was ejected from the vehicle. It’s unclear what his current condition is, but he was flown to Renown Regional Medical Center in Reno, Nevada.

Photos from the scene showed the cabin of the truck hanging off the bridge as the rest of the truck sat overturned on the highway.

Traffic snarled as crews worked to clear the scene. The Caltrans QuickMap showed eastbound I-80 traffic remained backed up in the area at 8:45 p.m. Friday.

“Expect significant delays,” CHP’s Truckee office said Friday evening. “There is a substantial traffic backup in the area, and emergency personnel and equipment remain on scene. Please slow down, use caution, and give crews plenty of room while traveling through the area.”

CHP reopened eastbound I-80 near Floriston around 1:37 a.m.

The cause of the single-vehicle crash is still under investigation.

Nevada County is just east of Lake Tahoe and near the west slope of the Sierra Nevada Mountains.