The outage affected approximately 4 million customers across Southern California, parts of Arizona and northern Mexico.  The Los Angeles Times reported the outage stranded people on rides at Sea World in San Diego and Legoland in Carslbad.  Area hospitals were forced to use backup generators to maintain services.  The San Diego airport was forced to close to departing flights because of the power outage.

Officials say the outage was the result of a Pinnacle West electrical worker removing equipment in Yuma, Ariz.  The company is investigating why protection protocols failed causing such a widespread interruption of service.