A tsunami warning issued Saturday for Whidbey Island and other areas of Puget Sound made few waves, but state and county officials have long warned about the possibility of a tsunami striking the island.
The advisory was issued after a volcano erupted near Tonga in the Pacific Ocean. Areas included in the alert are Whidbey, Camano and the San Juan islands and areas to the west.
Experts warn that waves generated in Asia would have a straight shot down the Strait of Juan de Fuca and would strike the west side of North Whidbey most directly. Estimated areas of inundation on Whidbey include West Beach, Naval Air Station Whidbey Island, Admirals Cove, Lagoon Point, Bush Point, Useless Bay, Dave Mackie Park and Cultus Bay.
The maps can be viewed at www.islandcountywa.gov/DEM/Pages/IslandCoTsunami.aspx.
A 2021 study by the Washington State Department of Natural Resources describes the impacts a magnitude 9.0 earthquake on the Cascadia subduction zone would have on Puget Sound communities. The study finds that the first tsunami waves would reach Whidbey Island within an hour and a half after the earthquake. The waves could inundate shorelines for as long as 14 hours.
In the event of a tsunami predicted to affect Island County, a warning will be issued through the Emergency Alert System, or EAS. The EAS is the nation’s public warning system and will be broadcast through cable television, radio stations and mobile devices such as cell phones.
Island County also has seven tsunami sirens installed around Camano and Whidbey islands. On Whidbey they are at Dugualla Bay, West Beach, Oak Harbor Marina, Keystone and Lagoon Point.
In the event of a tsunami warning, people are advised to get away from the shoreline and move as far inland as possible. Those on boats should head out to sea.
A University of Washington report explained that a tsunami is a surge of water that typically forms when an earthquake causes sudden movement on the seafloor and displaces a mass of overlying water.
“Tsunamis are typically not like breaking beach waves,” the report states, “but behave more like a surge of fast-rising water, and move much farther inland than high tides or storm waves.”
All marine shorelines in the state are vulnerable to tsunamis. The Pacific Coast, the Strait of Juan de Fuca and Puget Sound all have geologic evidence for past tsunamis, and future tsunamis are inevitable, the report states.