What would happen if a tsunami hit Snohomish County?
It’s occurred before, as recently as the early 1800s. Planners have given some thought to what that would mean today. They’ve devoted a whole chapter to the nightmarish scenario in the county’s 2010 Natural Hazard Mitigation Plan. Read the plan here.
In general, the hazard plan says, the county wouldn’t likely see significant tsunami impacts from an earthquake somewhere in the Pacific Ocean. Thank Whidbey Island, which sits like a shield to the west.
However, a big shake along the Seattle Fault could kick up a wave on Puget Sound.
People living and working along the county’s coastline would be at greatest risk, the plan says, with damage from a serious wave likely to create major mayhem in Everett, Edmonds and Marysville. The planners have even calculated how many people are at risk, the number of structures in harm’s way and the likely dollar value of the damage — although I haven’t read the plan closely enough yet to fully understand how they reach those conclusions.Tsunami have swept the coast of Snohomish County in the past. The best known example is the great wave that was kicked up by the collapse of Camano Head at the south end of Camano Island. That is believed to have occurred sometime in the early 1800s, and is said to have buried a small village and drowned members of local Indian tribes who were digging clams on nearby Hat Island.
Geologists also have found evidence of tsunami events at Cultus Bay and Possession beach on Whidbey island.
Meanwhile, Everett Community College geology instructor Alecia Spooner will talk about the earthquake in Japan and will answer general questions about tsunamis. at 11 a.m. today in EvCC’s Whitehorse Hall, room 352.
Here’s a report on statewide tsunami risk.