Tropical Storm Marie is expected to strengthen into a hurricane off Mexico while remaining well away from Southern California, but the system could still produce hazardous coastal conditions over Labor Day weekend.
National Weather Service meteorologist Rich Thompson said the forecast has Marie continuing west and northwest, moving farther from the coast. Forecasters consider a turn north toward Southern California extremely unlikely.
The greater concern for Southern California is the swell generated by the storm. Thompson said a large southerly to southeasterly swell is expected to move into coastal waters, bringing strong rip currents and large waves, particularly at south-facing beaches. Coastal flooding also is possible. The swell is expected to peak Sunday and Monday.
Those conditions arrive after a summer of high surf and recent shoreline damage. Storm surge has damaged Aliso Beach in Laguna Beach, while previous high surf and tides have caused coastal erosion elsewhere in Southern California. That existing damage could be relevant when adjusters investigate subsequent coastal property losses and determine the timing and cause of damage.
Beach activity also has been heavy. More than 1 million people visited Los Angeles County beaches last weekend, according to the reporting, and lifeguards conducted more than 1,200 ocean rescues amid high surf. Labor Day weekend could bring another large influx of visitors as Marie increases the hazards along the coast.
Marie also is expected to send tropical moisture into Southern California. Forecasters put the chance of receiving a half-inch of rain or less at about 50% and do not currently expect precipitation heavy enough to cause mudslides. The rainfall forecast remains sensitive to changes in Marie’s track.
For property and catastrophe adjusters, the distinction between hurricane landfall and remote storm effects may matter in documenting losses. The current forecast points to swell, waves, coastal flooding and limited rainfall as the principal potential sources of damage in Southern California rather than direct hurricane winds or a landfalling tropical cyclone. Existing erosion and prior storm damage could also complicate assessments of when coastal losses occurred.
Forecasters are continuing to monitor Marie’s path. A shift closer to North America could increase rainfall and ocean hazards, while a track farther offshore would reduce those effects.