How did tsunami impact SLO County? Here’s what happened overnight
San Luis Obispo County escaped damage after a tsunami advisory put all of the county’s coastline on alert Tuesday night and even prompted an evacuation warning in one low-lying area, following a massive undersea earthquake off the coast of Russia.
Nevertheless, the advisory remained in effect much of Wednesday morning as the lingering waves from the quake worked their way across the Pacific Ocean. The advisory and evacuation warnings were all eventually lifted as of 1:30 p.m. Wednesday.
The 8.8-magnitude earthquake was recorded west of the Aleutian Islands about 80 miles southeast of Petropavlovsk, on Russia’s Kamchatka Peninsula, on Tuesday afternoon.
Soon after, the National Weather Service issued tsunami watches and then upgraded advisories for coastal areas in California, Oregon, Washington, British Columbia and Alaska from the California and Mexico border to Chignik Bay in Alaska.
The tsunami was estimated to eventually reach Port San Luis by 12:35 a.m., bringing with it the potential for nearly 4-foot waves and strong seawater surge.
When the first surge waves did arrive, however, they didn’t create much of an impact.
When reached for comment Wednesday morning, a Port San Luis Harbor District official told The Tribune the district didn’t see any damage from the event.
Meanwhile in Morro Bay, all appeared calm overnight with no visible impacts from the tsunami between midnight and 1 a.m. A request for comment from Harbor Department officials was not immediately returned Wednesday morning.
National Weather Service warns of ‘very isolated’ tsunami in SLO County
The last time a tsunami hit San Luis Obispo County was in 2011 after a devastating 9-magnitude earthquake rocked Japan, triggering a tsunami and causing a meltdown at the Fukushima Daiichi Nuclear Power Plant.
Locally, the Morro Bay Harbor experienced the largest impact from that event, which caused $455,000 in damages to piers and infrastructure.
And early Tuesday night, it appeared the region might be in for a repeat — though in a slightly different location.
Around 10:45 p.m., the Weather Service said it expected “very isolated low-end warning level tsunami conditions” at Port San Luis and Avila Beach once the tsunami arrive on local shores.
It warned of waves of up to 3.7 feet and a possibility of low-to-moderate levels of coastal inundation and surging of seawater in and out of harbors during that time.
Impacts would be most felt on beaches, harbors and low coastal roads, the Weather Service said, and people were urged to stay away from the water and be prepared to move to higher ground.
Concerns over potential damage even pushed the county to issue evacuation warnings for several low-lying neighborhoods of Los Osos on Tuesday night. Those warnings were lifted Wednesday afternoon.
Overall, however, no major impacts appear to have been felt across the region.
According to meteorologist John Lindsey, the tsunami “peaked at about 2 feet above the predicted water level” at 1:18 a.m. in Port San Luis.
The Weather Service additionally said around 2 a.m. that the Port San Luis gauge showed “a rapid and damaging surge, going from low to high tide in just a few minutes.”
The same gauge continued to show rapid fluctuations in water level in the area through mid-morning Wednesday, according to NOAA data.
People were reminded to avoid the beaches and low-lying coastal roads, as strong waves and surging water could last into early Thursday morning. Widespread inundation was not expected, the Weather Service said.
The advisory was expected to continue into early Thursday morning but was canceled early on Wednesday afternoon.
This story was originally published July 30, 2025 at 1:08 PM.
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