Pacific Northwest plans evacuation towers for tsunami that could kill thousands

Ocean Shores, Washington (Expedia, iStock)

It’s a looming disaster: Experts say a major earthquake off Washington state would trigger a tsunami on the Pacific Northwest coast, killing tens of thousands of people.

The wall of water would flood low-lying coastal areas of Washington, Oregon and northern California within minutes, leaving much of the region under 10 feet or more of seawater, the New York reported. Times.

“The fact is, if a tsunami happens tomorrow, we’re going to lose all of our kids,” said Andrew Kelly, superintendent of the North Beach School District, which includes Ocean Shores, Washington.

He is one of a growing number of local officials calling for a network of raised buildings and platforms along the coast to provide refuge for residents who would otherwise be doomed. Residents of Ocean Shores and nearby hamlets west of the state capital, Olympia, will decide on Feb. 15 whether to approve a bond measure to build the structures.

Washington state officials have proposed a network of 58 vertical evacuation structures along the outer coast that could provide 22,000 people with evacuation options. Each structure could cost around $3 million.

Scientists have warned for years of another catastrophic earthquake from the Cascadia ‘megathrust’ fault that stretches 600 miles from Vancouver Island, British Columbia to Cape Mendocino, California. The last big one happened in 1700.

An earthquake from the fault, about 70 miles offshore, could immediately drop the shoreline by several feet. The shock under the sea would send massive waves rushing towards the shore, hitting land within 15 minutes.

Many stretches of the northwest coast lack cliffs or tall buildings. The death toll could be unfathomable – surpassing any other natural disaster in US history, according to the newspaper.

As many as 70,000 Plains residents would be engulfed by the large tsunami, according to computer models from Washington State’s 9.0 magnitude earthquake. Half would not have access to heights.

In Oregon, between 5,000 and 20,000 people could die in a similar event. Additional deaths are expected in northern California. In Crescent City, a tsunami from Alaska in 1964 killed 11 people.

A catastrophic earthquake could cause widespread devastation to property and lives in an area of ​​140,000 square miles, including Seattle and Portland.

The probability of a 9.0 megaquake on the Cascadia Fault in the next 50 years is one in nine, according to the research. The probability of a smaller but still powerful earthquake above magnitude 7.0 is one in three. In other words, the last earthquake on the fault was in 1700, and scientists expect another big earthquake every 430 years. Include smaller but still powerful earthquakes and the timeline in some areas shrinks to every 250 years.

Few places are more vulnerable than Ocean Shores, where 6,700 residents live on a six-mile-long peninsula. A tsunami could put it 23 feet under water.

Those towards the southern end would be about eight miles from the heights. Many residents may only have 10 minutes after the shaking stops before being overwhelmed by the surge

[NYT] – Dana Barthelemy

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