Sonoma and Marin county beaches closed as tsunami from distant Pacific hits California coast
The greatest tsunami threat to the California coast in more than a decade closed beaches in Sonoma and Marin counties Saturday and prompted daylong safety warnings urging people to avoid a seashore that churned and surged for hours after a violent underwater volcanic explosion in the South Pacific more than 5,000 miles away.
The beach closures were only marginally effective at turning away visitors who came to the coast on an otherwise mild January day to see the spectacle unleashed on local shores.
At Sonoma Coast State Park, that show included heavy waves crashing into rock abutments and frothing high up past the normal tideline. A pod of bottlenose dolphins was spotted surfing through swells in the lineup.
The tsunami advisory issued before sunrise for the entire West Coast remained in effect Saturday night. Gauges along the California coast reported tidal surges of more than 3 feet, and videos showed coastal inlets brimming with ocean water in Marin and Santa Cruz counties.
Even weather experts were impressed.
“It goes to show the force of these currents because of the underwater eruption,” said Jeff Lorber, meteorologist with the National Weather Service in Monterey.
No major damage was reported in the state.
“I’ve seen a bunch of reports from Santa Cruz,” Lorber said. “That seems to be where the largest impacts are, flooding of roadways there, parking lots.”
The epicenter of the energy was a massive volcanic eruption near the Tonga Islands about 8 p.m. Pacific time Friday.
Satellite video and images showed a cataclysmic blast boiling from the sea high up into the atmosphere, emitting a shock wave that jolted island witnesses miles away.
Coastal communities from New Zealand to Hawaii and British Columbia to Japan were put on high alert, waiting for the arrival of swells seen as potentially hazardous for boaters, swimmers or others living and working close to the shoreline.
The tsunami rippled onto the California coast starting about 8 a.m., with surge activity and heavier surf reported from the Central Coast up to the Bay Area.
Residents, advised to stay off beaches, piers, docks and jetties, nonetheless came to the coast and nearby estuaries to witness it all.
In Santa Cruz County, people shared videos of waterways, including Soquel Creek and the San Lorenzo River, flowing backward due to incoming water from the tidal surge.
The Sonoma Coast has no official tidal gauge, but measurements from Point Reyes National Seashore in Marin County put the surge at 2.9 feet above mean wave height, while at Arena Cove in Mendocino County a later surge hit 3.7 feet above the median wave height, said Dave Snider, tsunami warning coordinator with the National Tsunami Warning Center.
Snider said the warning center had received no reports of injuries or death, and only minor reports about property damage.
“(It’s) wonderful, but we also know the initial investigation into damage is probably pretty early,” he said. “Hopefully, there’s not much.”
“We’re hoping the worst of the impacts is over,” Lorber said. Tides had mostly declined after the high tides of Saturday morning, he said.
The next high tide was forecast for 11 p.m. Saturday, Lorber said, and was not expected to be as high as the earlier high tide.
Rivers that drain to the Sonoma Coast, including the Russian and Gualala, did not see any significant change in near-shore levels as a result of the surges.
Saturday’s tsunami advisory was the first the Bay Area has experienced since 2018, though Lorber said that event expired more quickly and was less severe.
The tsunami triggered in 2011 by a magnitude 9.0 earthquake off the coast of Japan — and the crisis at the Fukushima Daiichi nuclear plant — did at least $48 million in damage to California harbors, mainly in Crescent City, as well as Fort Bragg and Santa Cruz.
Crescent City, in Del Norte County, has a long and tragic association with tsunamis. Since 1933, the city 20 miles south of the Oregon border has been hit by about three dozen of them, the worst in 1964 when an ocean surge spawned by the magnitude 9.2 Great Alaska Earthquake nearly wiped downtown off the map. Eleven people were killed by the rushing waters.
Crescent City’s highest surge Saturday measured at 3.7 feet above the mean tide, according to Snider.