The Blob, the Bluffs, and the Big Swell

Somewhere off San Diego right now, the Pacific is running a fever. Satellite maps of the eastern seaboard glow in furious reds and oranges from Baja to British Columbia, the visual signature of a marine heatwave that NOAA has been tracking since the spring of last year and that, by late summer, had already become the largest ever recorded in the Northeastern Pacific.¹ It is not a subtle event. It is not a one-week blip. And its fingerprints are showing up in three places at once: the water itself, the crumbling bluffs above it, and the surf arriving from a hurricane spinning more than a thousand miles away.

A Fever With a Name

Marine heatwaves are exactly what they sound like: sustained stretches of unusually warm ocean water, measured against a long-term baseline. Off California, researchers at Scripps Institution of Oceanography note that a temperature anomaly of roughly one degree Celsius above normal is enough to qualify, while two to three degrees counts as an extreme event capable of stretching hundreds of miles across the open Pacific.² The current event, which took hold in May 2025 and has persisted ever since, has pushed nearshore waters from San Diego to Santa Barbara five to ten degrees Fahrenheit above normal for the season, with NOAA forecasters giving it strong odds of continuing through the remainder of the year.¹

The mechanism is almost mundane in its simplicity: winds that normally blow south along the coast, cooling the ocean surface through evaporation and stirring cold water up from below, have weakened. Without that churn, heat simply accumulates.² The consequence, however, is anything but mundane, because warm water does not just sit there — it expands.

Six Inches Nobody Predicted

That expansion shows up on tide gauges as a straightforward physical fact: warmer water takes up more volume, so sea level rises even without a single extra drop being added to the ocean. Tide gauge data compiled against NOAA’s predicted tide models found Southern California running roughly six inches higher than forecast models expected in late August, with readings near the Channel Islands topping six inches above prediction and levels off Los Angeles running about five and a half inches high.³ Six inches sounds modest until it is added on top of an already elevated high tide, at which point it becomes the difference between water lapping at a seawall and water pouring over it.

Where the Land Gives Way

Nowhere is that taller platform more visible than in the sandstone bluffs of Isla Vista, in Santa Barbara County, where clifftop apartment buildings on Del Playa Drive have spent the better part of two decades in a slow-motion standoff with the sea. County officials estimate the bluffs there retreat an average of six inches a year, though a single storm can claw back several feet in one pass, and experts monitoring the erosion warn that the historic six-inch pace could accelerate considerably as sea levels climb.⁴ Aerial footage of the stretch, captured by USGS survey teams, shows a familiar and unsettling pattern up and down the California coast: decks cantilevered over open air, foundations undercut by wave action, and rust-colored cliff faces sheared away in vertical slabs.

Santa Barbara County has responded with tightening buffer rules — mandatory twice-yearly surveyor measurements for any structure within twenty feet of the bluff edge, and vacate orders for anything closer than the current safety threshold — a policy shaped directly by a string of balcony and patio collapses in recent years.⁵ It is coastal erosion working at the pace of bureaucracy: rules updated a little faster than the cliffs, in the hope of staying ahead of them.

Then Karina Showed Up

As if a warmer ocean and eroding bluffs weren’t enough for one season, the Pacific produced a hurricane. Karina formed off southwestern Mexico in late August, and by August 31 the National Hurricane Center had it as a compact but powerful major hurricane, packing sustained winds near 130 miles per hour roughly eleven hundred miles southwest of the tip of Baja California.⁶ Karina itself never threatened the U.S. coastline — its forecast track kept it churning harmlessly out over open water — but hurricanes do not need to make landfall to make themselves felt. Long-period swell radiates outward from a storm’s center for hundreds of miles beyond the wind field itself, and Karina’s reached the Southern California coast as sizable, well-organized surf even while the storm itself sat well over a thousand miles offshore.

The National Weather Service’s general guidance on ocean safety is unambiguous about what swell energy like that means for beachgoers: bigger, more powerful waves also mean stronger rip currents, and swimmers caught in one are safest swimming parallel to shore until free of the pull, rather than fighting directly against it.

And Karina wasn’t traveling alone. Satellite imagery from NOAA’s GOES-West platform captured a second system organizing in the hurricane’s wake on the same day, a reminder that the eastern Pacific’s unusually warm surface waters — the same marine heatwave reshaping the coastline from below — are also fueling the storms passing above it.⁶

A Coastline Under Compound Pressure

None of these three stories — the heat, the eroding bluffs, the swell — is really separate. A warmer ocean expands and lifts the baseline sea level a few extra inches. Those extra inches raise the floor that every wave, tide, and storm swell now builds on top of. And a warmer ocean is also better fuel for the tropical systems generating that swell in the first place. The California coast isn’t being hit by one unusual event this season; it’s absorbing three compounding ones, each making the others slightly worse.

None of it is happening in the abstract, either. It is happening under real buildings on Del Playa Drive, on tide gauges that keep coming in higher than forecast, and in the surf reports of beaches that look perfectly calm and are anything but.