A guy who didn't get out fast enough was drowned in his vehicle on Maldrum Bar in Milwaukiee recently when the normal tidal surge of the Willamette came up faster than he could deal with and swamped him. When the next Cascadia Subduction Zone earthquake, often called "The Big One", hits here, likely soon, the tsunami surge up the Columbia to the Willamette at Portland will likely exceed by several orders of magnitude the normal tidal surge.
Much of downtown Portland is at levels of 30 ft to 35 ft above sea level. The tsunami surge from the next Cascadia subduction zone earthquake could quite quite conceivably exceed 50 ft above sea level at Portland.
Plan accordingly.
