https://wdfw.wa.gov/species-habitats/living/species-facts/owls#common-owls

More than a dozen species of owls live in Washington. The great horned owl (Bubo virginianus)(Fig. 1,4) is the species most often seen and heard. It is the most widely distributed owl in both Washington and North America, occupying dense forests, open woodlands, clear-cuts, deserts, and urban environments, including golf courses, cemeteries, and parks with adjacent woodlots. However, except where noted, information about this species applies to most other owls.

That does seem to support an argument for the great horned owl, based on the location. The image there does look kind of like your owl.