About 13,000 western Sonoma County customers were without power for about 90 minutes on Friday, PG&E said.

The blackout at 4:36 p.m. covered a wide swath of west county, including Monte Rio, Mirabel, Salmon Creek, Fort Ross and Annapolis, said Karly Hernandez, a spokeswoman for the utility.

Power was completely restored about 6 p.m., she said.

The outage was attributed to equipment failure, with the specific cause under investigation, Hernandez said.