CHP officers early Sunday were investigating a motorcycle crash near Calistoga and Petrified Forest roads.
The motorcycle was laying under a guardrail, according to a passerby who reported the crashed bike at 5:47 a.m. Sunday, CHP officials said.
But there was no rider.
The passerby called out into the surrounding forest on the remote road that bridges Sonoma and Napa counties.
Officers also searched the surrounding area and asked hospitals to check for the rider among their patient rolls, according to the CHP log.
The rider still wasn't found at 9 a.m.
No more details were available.
— Julie Johnson