As winds in Napa County picked up on Monday, the electricity went down at more than 1,700 homes and businesses and the stoplights at a major Highway 29 intersection, PG&E reported.
Customers from American Canyon north to Calistoga lost service at various times during the day, during a cluster of at least 14 separate outages the utility said was linked to strong wind gusts across the North Bay.
Some 1,000 of the affected customers were in and around the city of Napa, with another 550 losing power in American Canyon, according to spokeswoman Deanna Contreras.
Among the sites affected was the Highway 29-Rio del Mar crossing in American Canyon, where traffic signals went dark along with other parts of the city shortly after 11 a.m., she said. Power in American Canyon was reported back by 12:37 p.m.
A power outage knocked out the traffic signals at Highway 29 and South Kelly Road, causing traffic backups Monday afternoon, Caltrans reported.
The signal outage occurred around 2 p.m., but didn't last long, Caltrans said.
Another 73 customers were blacked out in St. Helena, 65 in Calistoga and eight in Yountville, where a falling oak tree pulled down wires and also damaged a house on Creek Street.
PG&E received the first local reports of power interruptions shortly after 8 a.m. in Napa, with more coming in between 11 a.m. and noon, Contreras said. As of 3:45 p.m., the utility reported about 600 locations still lacked service.
The National Weather Service predicted diminishing winds Monday night and Tuesday, with freezing conditions likely in Napa on Tuesday night.