A tropical storm spinning several hundred miles off the coast of Baja California kept dangerous surf pounding Southern California beaches for a third straight day. Marie’s winds have not strengthened much and its center never came close to making landfall, yet the swell radiating outward from the system pushed waves and rip currents onto crowded shorelines from San Diego County north toward Los Angeles. Lifeguards along the coast reported the strongest pull in the water, not the wind on land, as the storm’s main hazard. The pattern is a familiar late-summer one for the region, where a storm can remain entirely offshore and still shape beach conditions across hundreds of miles of coastline.
Advisory 29 Tracks a Weak but Wide Storm
The National Hurricane Center’s early morning bulletin placed Marie near 25.5 degrees north and 126.6 degrees west at 2 a.m. Pacific time on September 8, with maximum sustained winds of about 45 mph and a minimum central pressure of 996 millibars. The storm was creeping west-northwest at roughly 8 mph, a slow pace that let its swell field linger over the same stretch of coastline for days rather than sweeping through and moving on.
Despite the modest wind speed, the National Hurricane Center advisory warned that dangerous beach conditions would persist along the coast of the Baja California peninsula and Southern California for the next couple of days, a reminder that a tropical system’s most dangerous effects onshore often have little to do with its official wind category. A storm classified only as a tropical storm, well below hurricane strength, can still generate a wide enough wind field over open water to build a swell capable of overwhelming even experienced ocean swimmers once it reaches the coast.
Rip Currents Remain the Storm’s Sharpest Edge
Ocean swell generated by a storm can travel far beyond the system’s own wind field, arriving onshore as long-period waves that build into powerful, fast-moving rip currents even on days that look calm from the sand. That mismatch between a quiet-looking beach and a violent undertow is what makes swell events like Marie’s especially hazardous, since swimmers and waders often misjudge the risk from shore. Rip currents are typically narrow, fast-moving channels of water flowing away from the beach, and they are responsible for the large majority of ocean rescues performed by lifeguards along the California coast during periods of elevated swell.
Along the affected stretch of coast, lifeguard agencies typically rely on colored flag systems and posted signage at beach entrances to communicate rip current risk to visitors who may not check a marine forecast before heading to the water. During a sustained swell event like this one, agencies often keep the highest-risk designation in place for days at a time rather than adjusting it hour by hour, since the underlying hazard from a distant storm’s swell tends to persist even when the surface water looks relatively calm between larger wave sets.
Los Angeles Sees Its Wettest September Day in a Decade
Moisture wrapped around Marie’s northern edge also reached inland, bringing Los Angeles its first measurable rain since April. The city recorded about 0.6 inches on Sunday, enough to make it the wettest September day in Los Angeles since 2015, according to Fox Weather. The rain fell over several days as bands of tropical moisture drifted north ahead of the storm’s slow track, a pattern distinct from the wind and surf hazards playing out along the immediate coastline. Measurable September rain is uncommon enough in coastal Southern California that even a fraction of an inch stands out against a summer dry season that typically stretches from May through October.
South-Facing Beaches Take the Brunt of the Swell
Beaches oriented toward the south and southwest, the direction swell from a storm this far off the Baja coast typically arrives from, saw waves build to around 10 feet at some breaks. Those south-facing stretches of coastline are geometrically exposed to swell generated by eastern Pacific tropical systems in a way that north-facing beaches are not, which is why lifeguard agencies tend to concentrate warnings and closures on specific breaks rather than issuing a blanket advisory for the entire coast. Surfers seeking out the larger swell and casual beachgoers unaware of the underlying hazard often occupy the same stretch of sand during events like this, which is part of why lifeguard staffing is typically increased at the most exposed breaks.
Coastal Flooding Adds a Second Hazard at High Tide
Beyond the surf itself, forecasters flagged minor coastal flooding as a risk around the times of high tide, when the combination of elevated water levels and large breaking waves can push seawater into low-lying parking lots, walkways and beach access points. Enhanced beach erosion was also expected to continue for as long as the swell held up, a slower-moving but longer-lasting consequence than the more immediately dangerous rip currents drawing most of the public warnings. Piers and jetties along the affected stretch of coast are typically the first structures to see wave overtopping during events like this, prompting municipalities to post temporary closures until the swell subsides.
Marie’s Track Keeps It Offshore Through the Week
Forecasters expected Marie to continue drifting west-northwest away from the Baja California peninsula rather than turning toward the mainland, keeping the storm’s own wind field over open water even as its swell continued reaching the coast. That offshore track is typical for eastern Pacific tropical systems this far north and west, since cooler ocean water and increasing wind shear generally cause them to weaken before they could threaten a direct landfall in Southern California.
The eastern Pacific hurricane season runs from mid-May through the end of November, and systems that form or wander this far north later in the season typically weaken quickly once they move over the cooler water off the California coast. Marie’s slow forward speed meant that process was expected to play out gradually rather than all at once, which is part of why forecasters kept the multiday beach hazard warning in place rather than framing the danger as tied to a single peak day.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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