From Malibu to Long Beach and Orange County, powerful swells have stripped away beaches, damaged homes and infrastructure, and exposed a difficult question: How much of Southern California’s coast can still be protected?
For generations, the Southern California coastline has looked almost indestructible. Its beaches are backed by expensive homes, highways, boardwalks, seawalls and some of the most valuable real estate in America. Yet the ocean has a way of exposing the limits of that confidence.
This September, unusually powerful waves tore into beaches from Los Angeles County to Orange County. In some places, sand disappeared almost overnight.
In others, waves reached roads and homes, damaged public infrastructure and exposed sections of coastline that had been buried beneath decades of sand.
In Malibu, coastal erosion helped trigger the collapse of a large section of Sea Level Drive, creating a massive sinkhole near a beachfront mansion and forcing officials to restrict access to 31 properties.
In Long Beach, waves damaged sections of the historic peninsula and forced evacuations. Farther south, erosion and flooding struck communities including Dana Point and Laguna Beach.
The immediate trigger was not a hurricane making landfall in California. It was the energy carried by long-period swells generated by a distant Pacific storm – Hurricane Marie – combined with unusually high tides and an already vulnerable shoreline.
Now the bigger concern is what comes next. California is heading into a potentially powerful El Niño winter, while scientists are also watching a coastally trapped Kelvin wave that could temporarily raise sea levels along the West Coast.
The result could be a coastline entering the winter storm season with less sand, weaker natural protection and less room for error.
The Ocean Does Not Need to Make Landfall to Cause Damage
Hurricane Marie never came close to making landfall in Southern California, but that didn’t matter. As Marie moved through the Pacific, it generated large swells that traveled hundreds of miles toward the California coast.
The National Hurricane Center warned that the resulting swells would produce dangerous surf conditions along Southern California for several days.
The National Weather Service in Los Angeles reported significant coastal impacts, particularly along south-facing beaches.
At the height of the event, some areas experienced waves of roughly 10 feet or more, while long-period swells pushed water unusually far up the beach.
That distinction is important. A hurricane does not have to arrive over land to damage a coastline.
The storm can transfer energy to the ocean, and that energy can travel outward as swell. In this case, the effect was amplified by tides and the existing shape of the beaches.
The National Weather Service identified several particularly vulnerable areas, including the Alamitos Peninsula in Long Beach, Catalina Island and the coastline stretching from Oxnard toward Malibu.
Officials warned of beach erosion, flooding of sandy areas, bike paths and parking lots, and damage to low-lying roads. The waves were therefore not simply a surfing phenomenon. They were effectively a moving geological force.
Malibu Became One of the Most Dramatic Examples
Malibu has long represented the extraordinary value – and extraordinary vulnerability – of Southern California’s coast. On September 8, a large sinkhole opened near Sea Level Drive after days of high waves, flooding and coastal erosion.
The collapse damaged a driveway and roadway, triggered a gas leak and threatened access to the neighborhood. The property reportedly belongs to actor Nicolas Cage, who purchased the oceanfront home in 2024.
But the celebrity connection is almost beside the point. The more important fact is that the collapse affected an entire neighborhood. The City of Malibu said 31 properties were placed under mandatory evacuation orders and red-tagged while the area was assessed.
Sea Level Drive is the only route in and out of the affected area, meaning that erosion was no longer simply a threat to private property. It had become a public-safety problem.
The city has said the affected homeowners’ association, working with licensed engineers and contractors, is responsible for overseeing repairs, while the city is coordinating permits and monitoring conditions.
Malibu has been dealing with coastal erosion even before this latest episode. In August, the city was already coordinating with Caltrans over erosion threatening Pacific Coast Highway, and emergency repairs had been carried out at one particularly vulnerable location.
That is a reminder that the September damage did not appear on an untouched coastline. It struck a shoreline that has been progressively engineered, developed and exposed to waves for decades.
Long Beach, Dana Point and Laguna Beach Are Also Feeling the Pressure
Malibu may have produced the most spectacular images, but it is far from the only place where the coast has suffered.
On the Long Beach Peninsula, powerful waves stripped away protective sand and damaged portions of the historic boardwalk. Ocean water reached homes and other structures, and some residents were temporarily evacuated.
In Orange County, the effects were particularly visible around Dana Point and Capistrano Beach, where waves and high tides damaged oceanfront properties.
Laguna Beach also reported serious sand loss and coastal erosion, prompting city officials to focus on emergency response and seawall repairs.
These locations are different geologically and geographically, but they share a basic problem: there is less physical space between the ocean and the things people have built.
A beach is not simply scenery. It is a buffer.
When a wide beach is present, waves expend much of their energy before reaching roads, seawalls, bluffs and buildings.
When storms remove that sand, the same waves can reach structures with considerably more force. That is why the disappearance of a few feet of beach can suddenly become an engineering emergency.
How Much Is Nature – and How Much Is Human Responsibility?
There is no single culprit. Coastal erosion is a natural process. Waves constantly move sand, taking it from one location and depositing it somewhere else. Storms can dramatically accelerate that process.
Southern California’s coastline is particularly dynamic. Sand moves alongshore, rivers and streams contribute sediment, cliffs erode, beaches grow and shrink seasonally, and submarine canyons can remove sediment from the coastal system. But humans have changed the system.
Development has placed houses, roads and infrastructure very close to the ocean. Seawalls and other hard structures can protect individual properties, but they can also alter how waves interact with beaches and interfere with the natural inland movement of the shoreline.
The California Coastal Commission explicitly warns that rising sea levels can increase erosion and wave impacts, while shoreline armoring can accelerate the loss of beaches by preventing them from migrating inland.
There is another human factor: sediment. A beach needs sand. Southern California has enormous quantities of sediment in its broader coastal system, and a 2026 USGS study found that the region as a whole actually experienced more than 2 million square meters of net beach-area growth between 1984 and 2024.
That sounds reassuring – until the researchers looked more closely. Some beaches have suffered severe erosion while other locations have gained sand.
Human-built structures and natural convergence zones can concentrate sediment in some places while leaving other beaches short of it.
In other words, Southern California does not necessarily have a simple “not enough sand” problem. It has a sand-distribution problem.
That distinction matters because it suggests that some of the coastline’s future may depend less on creating sand from nothing and more on managing how sediment moves through the coastal system.
Rising Seas Make the Same Waves More Dangerous
The longer-term problem is sea level. The California Coastal Commission says rising sea levels will increase flooding, wave impacts and coastal erosion. As the average water level rises, waves can reach farther inland and attack cliffs and beaches more frequently.
That does not mean every storm will produce more powerful waves. It means the same wave can start from a higher baseline.
Imagine a beach as a protective step between the ocean and a house. Raise the ocean by several inches, remove some of the sand and then send a large swell toward the shore. The wave does not have to become dramatically larger to become more destructive.
This is why scientists increasingly look at several factors together: wave height, wave period, tides, sea level, rainfall and the condition of the beach before a storm arrives. The danger comes from their combination.
And Then There Is El Niño
The September episode has another uncomfortable feature: it may be an early warning rather than the main event.
NOAA says El Niño is strengthening and has more than a 90 percent chance of becoming a very strong event during the Northern Hemisphere fall and winter of 2026-27.
For California, El Niño can alter storm tracks, increase rainfall and contribute to higher coastal sea levels and larger waves.
The California Coastal Commission is already warning residents to prepare for strong storms, heavy rainfall, high waves, flooding and erosion during the coming winter.
The commission notes that the exceptionally strong 2015-16 El Niño produced unusually large waves and significant beach erosion along the West Coast. That is why scientists are paying attention to what happened in Southern California this September.
A coastline that has just lost substantial quantities of protective sand is entering a winter in which the ocean may repeatedly test it.
Could a Kelvin Wave Make Things Worse?
There is another piece of the puzzle, and it is easy to misunderstand. A Kelvin wave is not a giant wave that surfers will see approaching California.
It is a large-scale oceanic disturbance associated with El Niño. Warm water and elevated sea levels can move eastward across the tropical Pacific and then propagate northward along the coast of the Americas.
NOAA Fisheries says scientists are watching for these coastally trapped Kelvin waves along the West Coast this fall.
Such waves can raise coastal sea levels by roughly 6 inches, although the effects vary by location and timing. That may sound small compared with a 10-foot swell, but it is no less dangerous.
A temporary rise in sea level can reduce the amount of beach available to absorb wave energy. If high water arrives at the same time as large waves or a high tide, the risk of flooding and erosion increases.
The important point is that the Kelvin wave does not create the destructive surf by itself. Instead, it can raise the ocean’s baseline and make subsequent storms more damaging.
How Long Will the Current Episode Last?
The most intense effects from Hurricane Marie were expected to be relatively short-lived. The National Hurricane Center said Marie-generated swells would affect Southern California for several days, and the National Weather Service expected the strongest impacts to diminish as the swell subsided.
But that does not mean the coastal problem ends when the waves become smaller. The sand removed during a major swell may take weeks, months or longer to redistribute. Some beaches recover naturally; others do not return to their previous profile before the next storm arrives.
And the broader threat is now shifting from one hurricane-generated swell to the developing El Niño season. So the correct way to describe the situation is not that Southern California is facing one endless episode of giant waves.
It is that one unusually powerful swell has exposed how vulnerable parts of the coastline are just as a potentially difficult winter approaches.
Can the Beaches Repair Themselves?
Sometimes, yes. Beaches are not static landscapes. Sand can be carried offshore during a storm and later return.
Longshore currents can move sediment from one section of coast to another. A beach that looks devastated immediately after a storm can partially rebuild during calmer conditions. That is the good news.
The bad news is that nature does not necessarily rebuild the beach where humans want it, or on the timetable humans need. A beach may recover naturally only to be eroded again by the next major storm.
In some locations, seawalls, roads, homes and other structures leave the beach nowhere to migrate. That is the fundamental conflict. The ocean can move, while a house cannot.
What Can People Actually Do?
There is no single engineering solution for the entire Southern California coast. One option is beach nourishment – bringing additional compatible sand to an eroding beach.
USGS has identified offshore sediment resources that could potentially be useful for nourishment projects in Southern California. But nourishment is not permanent. Waves can move the imported sand away, sometimes relatively quickly.
Another option is shoreline protection, including seawalls, revetments, and other structures, which can be seen in countless locations across Europe, many of which were built 40, 50, or even 60 years ago.
These can protect particular buildings or pieces of infrastructure, but California officials warn that hard armoring can reduce the ability of beaches to migrate and can contribute to beach loss.
There is also managed retreat: moving buildings, roads or other infrastructure away from the most vulnerable parts of the shoreline. It is the least politically comfortable option and often the most difficult financially and emotionally.
But in places where the ocean is repeatedly removing the land beneath a structure, moving the structure may ultimately be more realistic than trying to hold the shoreline in exactly the same position forever.
The state is also investing in better monitoring, sediment studies, beach nourishment planning and coastal adaptation. The challenge is that every stretch of coast is different.
What works in Oceanside may not work in Malibu. What protects a road may destroy a beach. What saves one property may change the sediment supply for the next beach down the coast.
The Real Question Is Not Whether California Can Stop the Ocean
It’s clear that it can’t. The more realistic question is how much of the coastline should be defended, where it should be defended, and where communities should allow the shoreline to move.
That debate becomes more urgent as sea levels rise and extreme coastal events become more consequential.
The September 2026 waves have provided a dramatic demonstration. A distant hurricane generated the swell. High tides helped push water farther inland. A vulnerable beach had already lost some of its protective sand.
Development placed valuable property and infrastructure directly in harm’s way. And a strengthening El Niño may bring more difficult conditions later in the year. None of those factors alone explains the damage. Together, they do.
Southern California’s beaches may rebuild some of the sand they lost. In places, the ocean will naturally repair part of the damage. But the coastline will not simply return to the way it was because the storm has passed.
For Malibu, Long Beach, Dana Point, Laguna Beach and other communities built along the Pacific, the future may increasingly depend on accepting a difficult truth: the goal cannot always be to keep the shoreline exactly where it is today. Sometimes the most effective way to protect the coast is to give it room to move.
Sources:
- National Hurricane Center – Hurricane Marie: NOAA/NHC – nhc.noaa.gov
- National Weather Service – Los Angeles/Oxnard: NOAA/NWS – weather.gov
- City of Malibu – Sea Level Drive Incident: City of Malibu – malibucity.org
- California Coastal Commission – Sea Level Rise Science: California Coastal Commission – coastal.ca.gov
- California Coastal Commission – El Niño and Coastal Hazards: California Coastal Commission – coastal.ca.gov
- NOAA Fisheries – Ocean Indicators and El Niño: NOAA Fisheries – fisheries.noaa.gov
- NOAA Climate Prediction Center – ENSO Diagnostic Discussion: NOAA/CPC – cpc.ncep.noaa.gov
- USGS – Southern California Beach Morphology and Sediment Dynamics: U.S. Geological Survey – pubs.usgs.gov
- USGS – Offshore Sand Resources for Southern California Beach Nourishment: U.S. Geological Survey – pubs.usgs.gov
- Associated Press – Malibu Coastal Mansion Sinkhole: Associated Press – apnews.com
- The Los Angeles Times – Southern California Coastal Erosion: Los Angeles Times – latimes.com
- San Francisco Chronicle – Hurricane Marie and Southern California Beaches: San Francisco Chronicle – sfchronicle.com
- The Guardian – Southern California Coastal Damage: The Guardian – theguardian.com
