A surge of water generated by Chile’s 8.8-magnitude earthquake rushed onto the shores of the Central Coast on Saturday afternoon, drawing many onlookers but no damage reports.
In Morro Bay’s harbor — shielded by the long sand spit and jetties — a small surge seemed to arrive about 3:30 p.m., briefly tipping buoys toward the shore.
The West Coast and Alaska Tsunami Warning Center had estimated that the surge would reach Port San Luis at 12:35 p.m.
The tsunami-driven surge added to higher surf from the weekend storm, said John Lindsey, a media relations representative with Pacific Gas and Electric Co. and Central Coast weather expert and columnist.
A high-surf advisory remains in effect until 9 p.m. today, according to the National Weather Service.
Lindsey likened it to the cycle of high and low tides — usually a six-hour process of waters rising and then receding — being compressed into a short period.
“You’re talking about something that takes six hours, and then you have this contracting the water within 20 or 30 minutes,” he said. “So the current would be much stronger.”
The quake prompted the warning center to issue a tsunami advisory. Though devastating waves were not expected, people were advised to stay away from California beaches as a precaution.
Senior Chief Kirk McKay of the U.S. Coast Guard station in Morro Bay said people should not venture onto beaches or marinas during these conditions.
“An advisory is to keep people away from beaches and marinas because there could be strong surges,” he said.
An advisory means a tsunami is possible. Forecasters warned there may be strong currents but did not expect widespread inundation or damage to occur.
The warning center advised that its effects could last for hours after the surge’s arrival, and the initial wave is not necessary the largest.
Diana Henderson, a forecaster with the National Weather Service, said an advisory is issued when waves are expected to increase in height by less than a meter.
The next and highest risk level, a warning, would be issued if a tsunami were imminent. It calls for more precautionary measures such as evacuations.
Nonetheless, Pismo Beach city officials cordoned off the pier and cleared people from beaches late Saturday morning.
In Santa Cruz harbor, its dredge dragged its anchor, and the pipe that pumps sand out of the harbor bottom coiled up on itself.
The Harbor Patrol there repositioned the dredge so it would not get damaged, and a boat hoist was knocked loose, officials there said.
Like Port San Luis, Santa Cruz presents a south-facing shore, so there was more potential for damage because the tsunami’s energy was coming northward, Henderson said.
There have been six tsunamis large enough to cause significant damage along the coast of California over the past 200 years, according to Gary Griggs, a Santa Cruz Sentinel columnist and director of the Institute of Marine Sciences and Long Marine Laboratory at UC Santa Cruz.
Crescent City on California’s northernmost coast was hit hard by a tsunami from the magnitude-9.2 Alaskan earthquake of 1964.
Water levels rose 8 feet, and much of the low-lying downtown area was inundated as waves washed 2,000 feet inland, drowning 11 people and destroying 150 businesses, according to Griggs.
Alia Wilson of the Santa Cruz Sentinel contributed to this report.