Major Outage Cuts Power to About One Third of San Francisco

Early on December 20 a morning power interruption expanded through the afternoon to affect roughly one third of San Francisco utility customers, cutting electricity for between about 125,000 and more than 130,000 homes and businesses. The outage began before midmorning and by midafternoon city and utility outage maps showed broad darkened areas on the west side and in northern neighborhoods, including The Presidio, Seacliff, the Richmond and Sunset districts, Golden Gate Park, parts of West of Twin Peaks, the Western Addition and portions of downtown.

Firefighters from the San Francisco Fire Department responded to a blaze at a Pacific Gas and Electric Company substation in the Mission district during the outage. Firefighters reported extinguishing the fire with carbon dioxide after shutting down power to the equipment. San Francisco Fire Department Lieutenant Mariano Elias said he was comfortable characterizing the substation fire as a contributing factor to the outages, adding that it was unclear whether the fire explained the entire sequence of failures.

PG&E and city officials said crews stabilized the grid by late evening and restored power to the majority of affected customers. The utility reported that about 100,000 customers had power restored by 11 p.m., and that the remaining roughly 30,000 customers could expect restoration overnight. PG&E told residents that the grid had been stabilized and that additional customer outages were not expected at that time. Investigations into the exact cause of the substation fire and the wider outage remained underway.

The outage carried immediate public health and safety consequences. The San Francisco Department of Emergency Management urged residents to call 9 1 1 only for life safety emergencies, to avoid nonessential travel, to treat down traffic signals as four way stops, to keep refrigerator and freezer doors closed, and to turn off major appliances to prevent surges. Transit agencies faced significant disruptions, with buses and trains bypassing some Muni and BART stations and officials warning of delays across the system. Road congestion mounted as traffic lights went dark in affected neighborhoods.

Restaurants, shops and small businesses that rely on steady electrical service were forced to close or curtail operations during a busy holiday weekend, compounding economic strains on service workers and small proprietors. Ride hailing and autonomous vehicle services suspended operations in parts of the city for safety reasons. Suzanne Philion, a spokeswoman for Waymo, said the company was focused on keeping riders safe and ensuring emergency personnel had clear access to do their work.

Beyond immediate disruptions, the outage highlighted longstanding equity and resilience concerns for a city with stark differences in housing and resources. Low income residents, older adults and people who rely on electrically powered medical equipment face greater risks during prolonged outages. City emergency management officials said they were coordinating with community organizations and shelters to support vulnerable residents if longer restoration became necessary.

As crews completed repairs and investigators examined equipment and operational logs, officials emphasized the need for a thorough review of system vulnerabilities and emergency response plans to reduce the likelihood that a single substation event could cascade into wide scale outages in a dense, diverse urban center.