A June 23 equipment failure at a Morro Bay switchyard around 9:25 p.m. caused power outages for nearly 150,000 Central Coast Pacific Gas & Electric customers. Some Morro Bay residents reported seeing an arch of electricity surge over some equipment at the substation, a utility spokesman said.
"We have reports of a flash-arch," Pacific Gas & Electric Spokesman Blair Jones said. "As to whether that caused the blackout is still under investigation."
The outage affected customers from Solvang to Cambria, and caused almost total electrical darkness in San Luis Obispo and Santa Maria. Around downtown SLO, only parts of Cal Poly, the Broad Street firehouse, and Sierra Vista Hospital appeared to have power. Most traffic lights went out except for those along Madonna and Santa Rosa Streets.
Many homes and businesses in downtown SLO also experienced a brownout for approximately five minutes before the power went out completely.
The blackout occurred on the night when a full moon passed closest to the earth -- a so-called supermoon. The bright moonlight illuminated an unseasonably thick blanket of nighttime fog that provided enough visibility for residents to move around in the darkness without flashlights. A small group of blackout watchers assembled on Terrace Hill.
PG&E began restoring Central Coast neighborhoods to service after midnight and had most of the affected area online by 1:45 a.m.