Tsunami Vertical Evacuation Adds Twist To Earthquake Drill On Northwest Coast

Oct 15, 2015

More than 1.5 million Northwesterners signed up to take part in this year's "Great ShakeOut" on Thursday morning. While "drop, cover and hold" is part of the annual earthquake safety drill everywhere, some coastal schools and offices followed up with tsunami evacuation practice.

Tsunami warning sirens wailed along the Washington coast, but at North Beach Jr/Senior High School, there's no nearby high ground. So more than 300 students, teachers and visitors hunkered down on the top floor -- which is only the second story.

"This is the high ground," school Principal Brett Mackey said with an uncomfortable chuckle.

Tsunami inundation maps suggest the second floor might stay dry.

"Obviously, it would be nicer if we were up another 15 to 20 feet. It would give you a little more comfort,” Mackey said.

But he added, ”This may be the best place to be right now just because of the concrete structure" and earthen berm facing the ocean.

The most recent tsunami inundation map prepared by Washington's Department of Natural Resources put the North Beach school grounds at the edge of the area swamped by a "moderately high runup from the modeled Cascadia subduction zone tsunami."

A similarly situated school district in Westport, Washington, is currently building a new gym with a reinforced roof that can double as a tsunami refuge. The Westport and Ocean Shores communities both sprawl across what are basically long sand spits.

Down the coast, two other low-lying communities are planning another kind of tsunami safe haven. In Long Beach, Washington, and the Fairhaven neighborhood in Humboldt County, California, residents have proposed tall earthen mounds -- a berm, artificial hill or "tsunami mountain". The one about to enter the permitting phase in southwest Washington is being designed to hold more than 800 people on top.