Tsunami and earthquake experts will be in Westport and Ocean Shores on Wednesday for presentations focused on tsunami hazards, hazard alert messages and preparing residents for disaster with the ability to survive for up to two weeks.
Officials from the Washington Emergency Management Division will be joined by the Washington Geological Survey, the National Weather Service, the University of Washington/Sea Grant and Grays Harbor County Emergency Management officials in the 90-minute presentation, which will include time for questions.
The sessions are being called the Tsunami Roadshow. A South Beach presentation will take place at noon, Wednesday, April 11 at the Ocosta Junior-Senior High School Library, 2580 Montesano St., Westport; while a North Beach presentation will be 6 p.m., at the Ocean Shores Convention Center, 120 W. Chance a La Mer NW.
“We’ve done these presentations before, but we’re expecting more interest given the most recent Alaska Tsunami Watch event this past January,” said Keily Yemm, the tsunami program coordinator for the Washington Emergency Management Division. “Given how events unfolded, we think it’s even more imperative to help people understand the advantages of having a NOAA Weather Alert Radio, the difference in tsunami alert levels, near source vs distance source tsunamis and when the tsunami sirens will be activated.”
There are currently 23 sirens in Grays Harbor (including one located at the Quinault Indian Nation) out of 69 located in tsunami threatened coastal communities across the entire state.
The outreach campaign is partially funded by the National Tsunami Hazard Mitigation Program, which is also providing funding this year for more tsunami evacuation and hazard zone signs in tsunami threatened communities, new tsunami inundation modeling studies and the development of a best practices guide for building vertical evacuation structures in Washington, as well as other efforts.
Yemm said the history of tsunamis along the coast can be traced back for hundreds of years: “You go dig in the dirt in a few places along the coast, and there are tsunami deposits all along there.” One of the issues faced on the Northwest coast is that there are no written records where evidence found geologically can be compared to reports of major earthquakes.
“The only records we have are the oral histories from our Native Americans,” she noted, calling the segment during the Tsunami Roadshow an attempt to add “new science” to the historic presentation. The goal is to give the public “the most relevant information for their area,” Yemm said.
The state DNR on March 26 released new coastal tsunami inundation maps that show the potential impacts of a simulated 2,500-year event from a magnitude 9.0 earthquake.
The new maps are a bit different than previous tsunami inundation mapping, according to Charles Wallace, deputy director of Grays Harbor County Emergency Management. Previous inundation mapping was based upon the last Cascadia Subduction Zone earthquake from 1700.
The first tsunami waves (a minimum of four are expected) will arrive within 15-25 minutes following the quake. Aftershocks may produce additional tsunami waves in coastal areas. “The amount and level of inundation is our greatest concern,” Wallace said. The new maps show approximate inundation depths for this 2,500-year event to be anywhere from 67 feet at the North Jetty, 61 feet at Damon Point, or 57 feet at Ocean City, to 12.5 feet at the Westport Viewing Tower, or 26.2 feet at the Beachcomber Grocery and Deli in Grayland.
“There are a lot of new reports that are going to be published this year, and a lot new modeling projects are going to be started,” Yemm said of the new information that will be a part of the Tsunami Roadshow presentations.
One of the presentations includes walking maps to higher ground, with roads likely to be destroyed by an earthquake, and estimations of how much time it might take to make it to a safe area. School administrators in Westport suggested the event there include a tour of the new gymnasium at the Ocosta Elementary School, which is a vertical tsunami evacuation structure and the first building of its kind in North America,.
Yemm said attendees at the Westport event will be invited to take part in a tsunami evacuation drill to climb the stairs to the top of the vertical evacuation structure, typically not open to the public.
“Later in the presentation, we are going to get into vertical evacuation structures and how our state is pioneering those,” Yemm said. “There are a lot of new (proposed) projects. The interest is definitely there, but it’s just a huge funding issue.”