You are forgiven if tsunami is not at the top of your list of concerns at the moment. Global pandemic has a way of resetting priorities.

Nevertheless, the California Office of Emergency Services, in conjunction with other state agencies and academic partners, released updated Tsunami Hazard Area Maps last week, and it was a bit of a wake-up call for residents of the San Mateo County coast.

The map shows a larger area at risk of inundation from tsunami in Pacifica than previously considered. The state says the threat now exists through a significant portion of Linda Mar, including the Linda Mar Shopping Center. A worst-case tsunami could spell trouble for all of Rockaway Beach Plaza, and for much of the city that lies north of Sharp Park Golf Course and west of Highway 1.

You may think tsunamis are rare here. In fact, there have been 150 tsunamis along the California shore since 1800, though most produced little more than a ripple. A tsunami caused by an Alaskan earthquake in 1963 led to the evacuation of thousands of Coastsiders and damaged some boats at Pillar Point Harbor. There have been at least two tsunami warnings on the San Mateo County coast since 2005.

The Pacifica Police Department takes the threat seriously. Earlier this month, the force practiced its response for an eventuality that isn’t common but could cause calamity. It corresponded with California’s recognition of Tsunami Preparedness Week.

As with most of our existential threats, a little knowledge and planning go a long way.

Take a look at the maps yourself. The interactive maps from the California Geological Survey allow residents to plug in their own address. The message is simple: If you are in an area shaded yellow, be prepared to move east and into an area shaded green should you feel a prolonged earthquake or if you get a warning to do so.

The maps consider a 9.3 magnitude earthquake in the eastern Aleutian Islands, a worst-case scenario for our part of California. Experts say that would give rise to tsunami waves that would reach our coast in about five hours. If that seems like a lot of time, consider the panic that would arise as entire neighborhoods worked to evacuate at the same time with little notice.

These new maps are released near the 10th anniversary of the Tohoku-Oki earthquake and tsunami in Japan. That deadly day informed our local response. “We’re using a thousand-year scenario as the baseline for our new maps, hoping to avoid the tragic loss of life experienced there,” wrote Steve Bohlen, acting state geologist for the state of California in a release accompanying the new maps.

Bohlen gives us the bottom line: “While damaging tsunamis are infrequent in California, if you’re on the coast, you need to be aware of this potential hazard.”

— Clay Lambert

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