City Of Mercer Island issued the following announcement on Nov. 24.
A house fire that began at 4:47am this morning in the 3800 block of West Mercer Way is now extinguished, but control work, including an overnight fire watch, still continues onsite. The residence, which was initially reported to be in the 3500 block, was unoccupied and there are no injuries. West Mercer Way in this location was closed for most of the day, and is now reopened to traffic in both directions.
The initial response consisted of 4 fire engines (two originating from MIFD), 2 ladder trucks, 1 Medical Service Officer, 1 medic unit, 1 aid unit, and 1 additional Battalion Chief. The site was difficult to access and the house had a very complex construction, prompting the Incident Commander to upgrade the event to a "Second Alarm" and bringing an additional 3 fire engines, 1 ladder truck, 1 Battalion Chief, 1 aid car, and 1 air unit.
In total, approximately 50 Firefighters were on scene at the apex of this significant fire, including crews from Bellevue Fire, Kirkland Fire, Redmond Fire, and Eastside Fire, under mutual aid agreements. The cause of the fire is under investigation and undetermined at this time. There will be a three-person fire engine crew remaining on scene to watch for any reemergence of flames or smoke for approximately 24 hours or until it is deemed no longer necessary.
Original source can be found here.