A sign is displayed on the window of Bamboo Asia restaurant during a power outage in San Francisco, Friday, April 21, 2017. 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. Pacific Gas &#038; Electric crews were assessing the problem and there was no immediate estimate for restoration of electricity. (AP Photo/Jeff Chiu)