information from the City of Burien

The City of Burien has worked throughout the day with geotechnical specialists to assess conditions at the site of the mudslide that damaged two houses north of Seahurst Park last night. Preliminary reports indicate that the slope has not stabilized and evacuation orders remain in effect. Residents of all five evacuated homes are to remain away from their houses overnight but, except in the case of the most-impacted house, residents will be allowed back to retrieve belongings under supervision for short periods of time.

Details of Geotechnical Review:

The slide began at approximately 150 feet elevation – about half way up the slope – where soil composition changes. Above that point, ground water is absorbed. It then seeps out below that elevation. Given wet soil conditions over the past several days, seepage behind the slope’s surface layer likely caused the soil to blow outward, resulting in the slide.
The source of the slide and much of the debris field lies within the property lines of the southernmost house.
It is typical in slides like this one for the margins to continue settling. This will be particularly likely as rains return overnight and throughout the coming days.

Details of evacuation status:

Access to the southernmost property is prohibited. The public is asked to stay away from the area as further settling remains likely. Signs will be posted at the north end of Seahurst Park to prevent public access from below the slope.
The property owner of the second-most southern property will be allowed to return to collect personal items briefly and under supervision. The stability of the slope above that property remains in question and further settling is likely.
Property owners in the remaining three evacuated houses will be asked not to reoccupy their homes until they are able to demonstrate through an independent geotechnical study that it is safe to return.

Other updates:

The City is working with the Fire Department to secure the vehicle that was pushed past the bulkhead in the slide. At this time, there is no access to be able to tow the vehicle out of the water. Staff on site indicates that there is no evidence of oil or gasoline leaking from the vehicle.
The Homeowners’ Association has asked the public to respect their privacy at this time.

Updates will be provided at www.burienwa.gov under “News & Announcements” as information is available.