Fortunately, the tallest tsunami was from a rockfall in a fjord[1], not from a subduction zone earthquake. They are typically ~10 m, and it's really the wavelength, not the amplitude, that is a problem because there is so much water that the inundation is more like a flash flood than a quick slap from a breaking wave.
Second, I don't believe tsunamis from subduction zone earthquakes on the Cascadia trench will impact Seattle that much, because (as you may be able to see from your location) the Olympic peninsula is in between you and the trench. The wave coming through the Strait of Juan de Fuca will spread outward into Puget Sound and mostly dissipate against Camano and Whidbey Islands.
The big tsunami hazard for Seattle itself is the from an earthquake on the Seattle fault[2].
There's a seiche hazard in Seattle, though. Lake Washington will slosh back and forth in resonance with the shaking. Basically every natural feature in the Pacific Northwest has some exotic way of killing you.
Second, I don't believe tsunamis from subduction zone earthquakes on the Cascadia trench will impact Seattle that much, because (as you may be able to see from your location) the Olympic peninsula is in between you and the trench. The wave coming through the Strait of Juan de Fuca will spread outward into Puget Sound and mostly dissipate against Camano and Whidbey Islands.
The big tsunami hazard for Seattle itself is the from an earthquake on the Seattle fault[2].
[1]: http://geology.com/records/biggest-tsunami.shtml [2]: https://www.youtube.com/watch?v=n2AGlhuCQ-A