From the California Highway Patrol:

On April 6, 2018, at approximately 1310 hours, Humboldt Communications Center (HCC) received a report of a vehicle over the side of a steep embankment on US-101, south of Dora Creek in Northern Mendocino County. Upon the arrival of emergency personnel, the involved vehicle was completely submerged in the Eel River. The California Highway Patrol, Southern Humboldt Technical Rescue, Piercy Volunteer Fire, and Leggett Volunteer Fire Department all responded to the scene to assist, however due to the strong river current, and the poor clarity, the vehicle was unable to be located. CHP and emergency personnel have continuously searched and monitored the river in attempts to locate the vehicle. CHP has also utilized its helicopter in attempts to locate the vehicle.

At this time, the collision remains under investigation by the Garberville CHP.