AP) — A power outage struck a wide area of San Francisco on Friday, blacking out about 90,000 utility customers, snarling traffic as intersection signals went dark and stopping the famed cable cars for a time.

The series of outages began affecting the city at 9 a.m., said Tamar Sarkissian, a spokeswoman for Pacific Gas & Electric.
Crews were assessing the problem and there was no immediate estimate for restoration of electricity.

Local media reported firefighters and utility crews were at a smoky fire at a substation but there was no word on whether it was related to the outage.

“Power outage in the Northern & Central part of SF,” the San Francisco Department of Emergency Management tweeted, urging the public to refrain from calling 911 unless it is a life-safety issue.

The outage affected the Financial District, including Bay Area Rapid Transit’s downtown Montgomery Station.

People used the lights of their cellphones to walk through the darkened station before BART stopped service there.

The San Francisco Chronicle reported the outage also affected the Presidio, and KRON-TV reported effects stretched to the Marina/Cow Hollow area.

San Francisco has a population of about 850,000.