A utility worker doing maintenance near Yuma, Ariz., triggered a massive blackout that jammed roads, closed schools and businesses, grounded planes and left more than 4 million people across a large swath of Southern California and Mexico without power.
The blackout Thursday brought routine life to a halt. Many offices closed, but workers endured gridlock getting home because traffic lights were out. Officials said they noticed an increase in fender-benders in some areas as drivers tried to navigate the roads.
People were trapped in elevators and on rides at Sea World in San Diego and Legoland in Carlsbad. Hospital emergency rooms switched to backup generators, while outgoing flights from San Diego were canceled for several hours.
Customers jammed those stores that remained open, stocking up on ice and candles as utility company officials warned that power may not be restored until late Friday. Officials canceled classes Friday at most colleges and schools in San Diego and surrounding communities.
"Get ready to be in the dark. Get your emergency precautions ready," said Michael Niggli, president and chief operating officer of San Diego Gas & Electric.
The blackout was triggered by a mishap on a high-voltage power line linking Arizona and San Diego, causing a cascading series of electrical grid failures stretching into Southern California.
APS, which is Arizona's largest electric utility, said a worker was doing maintenance on lines at a nearby substation when the blackout occurred.
"The outage appears to be related to a procedure an APS employee was carrying out in the North Gila substation," an APS spokesman said in a statement. "Operating and protection protocols typically would have isolated the resulting outage to the Yuma area. The reason that did not occur in this case will be the focal point of the investigation into the event, which already is underway."
Despite temperatures that reached into the 100s in San Diego and Imperial counties, excessive electricity demand didn't appear to be a factor in the power loss, said Stephanie McCorkle, a spokeswoman for the California Independent System Operator, the agency that oversees most of California's electrical grid.
"It was not a case of a high-demand day," she said. "The operating reserves were fine."
Utility crews were scrambling to restore some power by tapping into local energy sources at gas-fired plants in Escondido and Otay Mesa, officials said. By Thursday night, power had been restored to some communities in Orange and Imperial counties, but power wouldn't be fully restored until Friday, officials said. Portions of Baja California as well as Arizona were also without power.
The blackout caused disarray across the region, interrupting Amtrak trains and trolley service in San Diego and causing gasoline station closures. House alarms shrilled. Several sewage pumps failed during the blackout, sending effluent into San Diego Bay.
Residents of a nursing home in Indio in Riverside County were evacuated when their facility lost power, and county officials opened a cooling center. At San Diego International Airport, dozens of travelers were left stranded when their flights were canceled.
In downtown San Diego's usually bustling Gaslamp district, most businesses were closed. In Oceanside, people shopped in a dark 99-cent store, and some cashiers tallied bills by calculator.
San Diego County hospitals were operating on backup power, but conditions were challenging staff at Scripps Hospital in La Jolla, which had 220 patients when the power went out.
"We are in full disaster mode," said Gary Fybel, chief executive of the hospital. "We completed all surgeries that were underway. We did not take on new surgeries, [and] delayed nonessential treatments."
The hospital staff conducted its regular meetings by flashlight just outside the main entrance of the hospital. Many hospital rooms were illuminated with power produced by generators.
In San Juan Capistrano on Thursday evening, two gas stations off Interstate 5 were lined with about a dozen cars after motorists ran out of gas. They hoped to fill up at the stations, but without electricity the pumps didn't work. Some said they were waiting for friends and relatives to bring them gas or to drive them home. Some said they might need to sleep in their cars.
At a Best Western Inn next door, a power generator was keeping the lights on.
"We're struggling, it just wiped everything out: no computers, no phones, no credit card scans," said Dustin Armenta, a hotel clerk.
Times staff writers Andrew Blankstein, Marc Lifsher, Joel Rubin, Tony Perry, Nicole Santa Cruz, Robert J. Lopez, Ruben Vives, Victoria Kim, Kurt Streeter, Christopher Goffard, Alexandra Zavis, Molly Hennessy-Fiske, Scott Gold, Rong-Gong Lin II and Phil Willon contributed to this report.