9:18 AM: Seattle City Light estimates the power outage affecting a section of southwestern West Seattle might not be fixed until after 1 pm. SCL says “equipment failure” is to blame for the outage at 77 homes in The Arroyos. (Thanks to Susan for the tip.)

3:55 PM UPDATE: The estimates of power-restoration time have moved back, and we checked with Scott Thomsen of SCL about the status:

There is a crew working on this outage. We know that it involves underground equipment. We do not yet know what piece of equipment failed or where that failure took place. The crew is troubleshooting the system to locate the problem and identify it so they can make repairs. The … estimate for restoration of service is only an estimate and could change once the crew finds the damage and determines what is needed to fix it.

11:50 PM UPDATE: Looks like it’s finally over as of late tonight, after, as is pointed out in a comment, growing at one point to almost 200 homes. We’ll ask SCL again tomorrow what the cause turned out to be.

TUESDAY MORNING UPDATE: Turns out it was not entirely resolved – see comment below – so we checked with SCL’s Thomsen again this morning:

Yesterday crews found that an underground cable failed, which caused the outage. They switched around the damage to restore power. A permanent repair involving the replacement of the cable is being scheduled.

Today, crews are investigating an outage on that same circuit. This is limited to equipment in a single underground vault. They are working to determine what piece of equipment failed. It is possible that the two events are connected. If the vault equipment failed first, it could have caused a surge that the cable could not withstand.

When the crew identified the failed cable, they believed they had discovered the problem and restored service to all customers. In some cases like this, a customer’s call to tell us they are still out is how we learn that there is other damage that needs to be fixed.