A big earthquake along the Cascadia fault could cause Washington’s coastal lands to suddenly drop nearly 7 feet, instantly increasing the flood risk to beachside communities, new research shows.
Why it matters: The areas expected to be hardest hit by subsidence — including Oregon and Northern California — are home to tens of thousands of people, five airports and more than a dozen critical facilities, including hospitals, schools and fire stations.
Threat level: Washington’s coast faces some of the most extreme impacts in the Cascadia earthquake subsidence study — with deeper land drops and broader floodplain expansion than in Oregon or California, per the study published last week.
- The Washington models extend up to 18.6 miles inland, more than in Oregon or California, reflecting the state’s coastal topography.
- Grays Harbor and Willapa Bay could sink up to 5.9 and 6.7 feet respectively, per the study.
- Long Beach, Tokeland, Ocean Park and Raymond — and parts of Grays Harbor, including Ocean Shores, Westport and Aberdeen — are among the most vulnerable communities .
What they’re saying: Significant sinking would complicate and delay rescue and recovery efforts in the immediate aftermath of the large quake, but in the long term it “could render many coastal communities uninhabitable,” the study’s authors wrote…