A fishing village in far Northern California saw the largest tsunami waves in the state early Wednesday, though its warning was downgraded to an advisory by midmorning.
Crescent City, a community of 6,700 people that is 25 miles south of the Oregon border, registered tsunami waves at 4 feet in the predawn hours, according to National Weather Service officials.
“It was a long night for all of us,” said City Manager Eric Wier in a briefing on Wednesday. “We were fortunate this time. There was significant tsunami surges. We’re still dealing with those now, but it did stay within the banks of Elk Creek.” The wave heights actually reached 8 feet, because the 4-foot tsunami waves came on top of a 4-foot high tide, he said.
The city’s downtown, Wier said, “is at a high enough elevation that it is open.”
Crescent City, which is the county seat of Del Norte County, is particularly prone to tsunamis, with dozens striking over the past century. The reason is unusual geology: Just off the coast, an underwater ridge called the Mendocino Fracture Zone “funnels tsunamis into deeper water where they pick up speed before they hit Crescent City,” according to city literature.
“Crescent City is very unique in that very, very rarely is that first wave (the biggest),” said Ryan Aylward, warning coordination meteorologist for NWS in Eureka, on Tuesday night. “The largest waves are often multiple waves after.”
The roughly 100 boats docked at the Crescent City Harbor were directed by the harbor patrol to leave the area before the waves struck and head to deeper waters, where they could be safer.
“The captains are all leaving in parade fashion, one vessel after another,” Justin Hanks, lieutenant for the Crescent City Harbor District, told the Chronicle by telephone on Tuesday. “They’ve been through this a few times.”
A 2011 tsunami following a 9.0-magnitude earthquake off Japan lashed Crescent City with wave heights of more than 8 feet, smashing docks, sinking dozens of boats and turning the harbor into what the Chronicle described at the time as a “pool of wooden chunks and splinters, with boats and pieces of boats floating haphazardly or jutting up from the water.”
Wier said this week’s tsunami carried a similar potential for damage as the surge in 2011. Then, the tsunami peaked with 9-to-10 foot waves, but its impact was lessened because it arrived during a negative 1-foot tide, he said, while on Wednesday, the tsunami peaked at 4 feet during a high tide measured at about 4 feet. Both brought strong, swirling currents that sloshed “like a bathtub” and caused damage, Wier said.
A $50 million plus renovation after the 2011 tsunami brought larger, deeper pilings, floating docks and a main attenuator dock designed to temper the impact of waves. Project engineers say the harbor can now withstand a once-in-50-years tsunami event, which could bring waves as big as 15 feet.
The upgrade made Crescent City the first “tsunami resistant port” on the West Coast,” according to harbor officials — and the infrastructure seems to have functioned as designed on Wednesday.
“This was a good test,” Wier said.
Harbormaster Mike Rademaker said the dock that was damaged Wednesday was intended to absorb the shock and be sacrificial.
“Absorbing the brunt of the surge helped to protect the interior docks,” Rademaker said. “We’re still doing some further damage assessments.”
Aidin Vaziri contributed reporting.
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