Update 9:35pm
Power has been restored.

Update 6pm
Power was quickly brought back online for thousands in West Seattle after a transformer in a vault failed on Saturday afternoon. Seattle City Light reported that only 136 customers were still affected at 3pm and that they expected to have the power restored completely before 9:25 PM.

Original post 1:40pm
Seattle Fire Dept emergency crews responded to call for "vault fire" in the 3900 block of Alaska Way SW around 1:25 pm on Saturday. One person contacted the Herald and said a manhole cover had blown off as a result of an explosion caused by failed transformer.

City light said via Twitter that power should be restored within a few hours.