Nearly 3,500 SDG&E customers near Carmel Valley were without power on Monday night due to an outage, according to the public utility's website.
The outage started at 9:57 p.m. It was affecting the North City West, Torrey Pines and Fairbanks Country Club areas, SDG&E's outage map shows. About an hour later, the outage was still impacting 3,419 customers.
Nearly four minutes after the outage began, the San Diego Fire-Rescue Department received a call about a transformer fire in the same area.
San Diego police say a resident on Exbury Court called after hearing a loud explosion. While on the phone, a second explosion was heard, and the resident said they saw a large flash of light, according to the San Diego Police Department.
Get top local stories in San Diego delivered to you every morning. Sign up for NBC San Diego's News Headlines newsletter.
Flames could be seen from a transformer at the nearby substation on Lansdale Drive, SDPD Officer John Buttle said. Power was out along Del Mar Heights Road at several intersections, Buttle added.
The cause of the outage is still being investigated.
Power was expected to be restored around 12:30 a.m. on Tuesday, SDG&E said. By 6 a.m., all power was restored in the area.