An undersea volcano erupted Saturday in the Pacific Ocean near Tonga, prompting tsunami advisories and evacuations along the California Coast, including San Francisco and the Monterey Bay where beaches closed as surging water flooded harbors and low-lying coastal areas.

Waves from the biggest tsunami threat to the West Coast in more than a decade arrived early Saturday morning with the rising morning tide and continued pulsating onshore throughout the day. All eyes were on the coast, and while the drama shut down the Santa Cruz Beach Boardwalk and disrupted the day for beachgoers, by sunset the Bay Area appeared to dodge significant damage.

The tsunami advisory for the Bay Area was canceled before 8 p.m. then canceled for Santa Cruz and Monterey Bay, including the Big Sur coastline, by 9 p.m. But it remained in effect in Del Norte County in the far north of California and between Ragged Point, just north of San Simeon, and Rincon Point, just south of Santa Barbara.

Californians along the coast woke up to the tsunami advisory – the second-most severe alert, short of a warning to seek higher ground for dangerous flooding – and the worst of the flooding occurred before 9 a.m. But National Weather Service meteorologist Cynthia Palmer warned it was too soon to relax: “It’s not a one-and-done — this is an all-day type of event.”

The waves were triggered by an underwater volcano in the Pacific Ocean more than 5,300 miles away at Tongatapu, the largest island in Tonga, which saw its own large tsunami waves early Saturday. Satellites captured the massive eruption from space, heard as far as Alaska 5,800 miles away.

In the Bay Area, officials urged residents to stay away from beaches, harbors and piers, while in Berkeley the fire department issued an evacuation order to the city’s Marina neighborhood. Berkeley officials later lifted the evacuation order. In Marin County, the harbor in Tiburon saw flooding.

So did the one in Santa Cruz, where the city harbor suffered $20 million in damage from a March 2011 tsunami that followed an earthquake in Japan. The waves Saturday flooded the harbor parking lot with about 3 feet of water, dislodged a dredge, damaged boats and washed waste bins into the channel.

“The tide was rising incredibly rapidly, we could see the surge coming in,” said Karl Isacson, a Santa Cruz resident who watched the harbor flood and also witnessed the damage in 2011, which he said was much worse.

The famed Beach Boardwalk nearby shut down and a surfing competition was called off for the day at the city’s legendary Steamer Lane.

“It’s a hard thing for all us surfers looking at beautiful, un-ridden waves,” contest director Andrea Swayne said.

There were no reports Saturday afternoon of major injuries locally, though two fishermen were taken to a hospital after being swept into the water at San Gregorio State Beach near Pescadero. In the afternoon, San Francisco firefighters and the Coast Guard rescued at least three surfers in distress, as rescue swimmers spent nearly an hour in the water.

The tsunami waves arrived “in pulses” throughout the day, the National Weather Service said, warning they would remain hazardous with the lowering afternoon tide. The advisory was expected to last into the evening.

“We still could see a foot or two of a tsunami amplitude come in even as the tide lowers and it can still run up the beach, grab you, your pets, your family, your loved ones and take you out to sea as it recedes,” said National Weather Service Meteorologist Brian Garcia. “So it’s still a dangerous situation out there.”

Bay Area weather officials have long warned that tsunamis are a common occurrence in the region, and that bad ones, while rare, could still strike. They have advised that residents who live near the coast stay up to date on alerts and tsunami advisories like the one issued Saturday.

Along the West Coast, the weather service reported the highest waves as of 11:15 a.m. of 4.3 feet at Port San Luis near Avila Beach, and 3.7 feet at both Crescent City, once devastated by a 1964 tsunami, and Arena Cove in Mendocino County. Waves reached 2.9 feet at Point Reyes, 2.4 feet in Monterey, 1.1 feet in San Francisco, 0.9 feet in Alameda and 0.7 feet in Richmond.

A Tsunami advisory was issued for the Pacific Coast from Alaska to Washington, Oregon and California Saturday morning after a volcano eruption in the Pacific Ocean near Tonga. This map from www.tsunami.gov shows the advisory in the Bay Area in orange. Click the image to see the full map. (www.tsunami.gov) 

Beaches closed up and down the coast. Luigi Oldani of Oakland packed his children into their van and drove away after hearing the evacuation order.

“You don’t want to take that chance,” Oldani said.

But plenty of thrill-seekers and others were drawn to the water to take a look.

“We’re not used to tsunamis around here,” said Berkeley resident Ben Hoz, a member of the Cal Sailing Club who was tying ropes around a sailboat with his friend, even though the club had officially closed for the day. “It’s kind of exciting. But if they get higher, I’ll get out of here.”

In Santa Cruz, Connor Kryger, a 16-year-old surfer who drove six hours for the surf contest, was itching to get in the water despite the “really gnarly currents and stuff.”

“It’s really all I want right now,” he said.

Up the coast at Rockaway Beach in Pacifica, Minda Yu of Berkeley was among a dozen people gathered to watch four surfers braving the high waves.

“They’re out of their mind!” she said.

Staff Photographers Karl Mondon and Ray Chavez and Staff Writer Martha Ross contributed.

PACIFICA, CALIFORNIA – JANUARY 15: Sgt. Ryan Bianculli keeps watch during a tsunami advisory at Linda Mar Beachl in Pacifica, Calif., Saturday, Jan. 15, 2022, after a large underwater volcano erupted in the Pacifica Ocean near Tonga. (Karl Mondon/Bay Area News Group) 
PACIFICA, CALIFORNIA – JANUARY 15: A surfer catches a ride during a tsunami advisory at Linda Mar Beach in Pacifica, Calif., Saturday, Jan. 15, 2022. The advisor was posted after a large underwater volcano erupted in the Pacifica Ocean near Tonga. (Karl Mondon/Bay Area News Group) 
PACIFICA, CALIFORNIA – JANUARY 15: A fisherman at Linda Mar Beach ignores tsunami advisory in Pacifica, Calif., Saturday, Jan. 15, 2022, after a large underwater volcano erupted in the Pacifica Ocean near Tonga. (Karl Mondon/Bay Area News Group) 
BERKELEY, CA – JANUARY 15: A sign sign is placed on the main door during a Tsunami advisory and evacuation order at Berkeley Marina in Berkeley, Calif., on Saturday, Jan. 15, 2021. (Ray Chavez/Bay Area News Group) 
BERKELEY, CA – JANUARY 15: Ben Salazar, left, along with his father Sammy Salazar, of El Cerrito, observe the bay for possible bigger waves than normal during a Tsunami advisory and evacuation order at Berkeley Marina in Berkeley, Calif., on Saturday, Jan. 15, 2021. (Ray Chavez/Bay Area News Group) 
BERKELEY, CA – JANUARY 15: A US Coast Guard helicopter flies over the Berkeley Marina during a Tsunami advisory and evacuation order in Berkeley, Calif., on Saturday, Jan. 15, 2021. (Ray Chavez/Bay Area News Group) 
BERKELEY, CA – JANUARY 15: A lone boat moves slowly in the bay during a Tsunami advisory and evacuation order at Berkeley Marina in Berkeley, Calif., on Saturday, Jan. 15, 2021. (Ray Chavez/Bay Area News Group) 

Source: www.mercurynews.com