LONG BEACH, Calif., July 31 (UPI) -- A power outage in Southern California on Thursday left thousands without electricity and backed up traffic on one of the Los Angeles area's busiest interstates, authorities said.
According to officials, the blackout was caused by a vault explosion and cut power to about 30,000 residents in Long Beach, the Los Angeles Times reported. By Thursday evening, utility workers had restored power to all but about a thousand residents.
However, the problem also stretched beyond Long Beach neighborhoods and onto surrounding freeways.
Officials said the outage forced the city to close the on-ramps to the 710 freeway -- which backed up traffic even further on Interstate 405.
The initial explosion prompted Southern California Edison to shut down three power substations so workers could make repairs, the utility said.
A cellphone video that captured the explosion Thursday afternoon was posted by KTLA-TV on its website.
It wasn't known exactly when all power would be restored, but the utility said some customers will continue to be without electricity into Friday, the Times report said.
The blackout is also expected to cause minor delays on the Metro's Blue Line, officials said.
A vault fire left about 6,000 Edison customers without electricity just two weeks ago.