The 10:15 a.m. crash also blocked the railroad tracks used by the Napa Valley Wine Train.
At least one occupant of the Lexus was taken to the Queen of the Valley Medical Center in Napa, according to the California Highway Patrol.
As of about 12:45 p.m., the southbound lane was open and northbound traffic was using a turn lane to get through the area, CHP Officer Jaret Paulson said.
Melodie Hilton, the Napa Valley Wine Train's marketing director, said the fallen power pole might shorten the train's route today between Napa and Saint Helena but there are sidings along the route where the train can turn around.
