Officials with the California Highway Patrol says 43-year-old Jose Gonzalez was riding his A-T-V southbound on Mitchell Avenue approaching the intersection of Mountain View Avenue.
They say Gonzalez made a sudden turning movement, which caused the ATV to overturn and he was ejected. Authorities say he was not wearing a safety helmet and suffered major head injuries.
Gonzalez was transported from the scene to Community Regional Medical Center.
An investigation is now underway to determine the cause of the crash.