King Tides Breach Coastal Defenses in California and Florida

Seawater flooded streets, homes, and businesses across beach communities in California, Florida, and the Carolinas this week. The inundation was driven by king tides triggered by the full moon earlier in the week. These gravitational alignments of the Earth, moon, and sun can occur several times annually and persist for multiple days.

Meteorologists identified additional atmospheric factors that intensified the flooding. Chris Fisher, a National Weather Service meteorologist in Miami, noted that strong high pressure to the north combined with low pressure over the Caribbean to amplify swells in Florida. On the California coast, Roger Gass, a meteorologist with the Bay Area forecast office in Monterey, cited the ongoing super El Niño for warming the ocean and increasing seawater volume. He also pointed to Kelvin waves, which are pulses of warm water that raise sea levels.

In Southern California, residents of Huntington Beach placed sandbags outside their homes on Wednesday. Some pedestrians used paddleboards and surfboards to traverse flooded streets. The Pacific Coast Highway saw multiple closures, and forecasters expected tides to approach record levels in Orange and San Diego counties.

In Northern California, high tides peaked 1.9 feet above normal levels. The weather service predicted minor flooding in low-lying shoreline areas through Saturday. Gass stated that coastal flooding typically occurs within an hour and a half before and after high tide.

Flood warnings covered most of Florida’s Atlantic coast through early Friday. Street flooding was reported in Charleston and Myrtle Beach, South Carolina, while rip currents posed a risk as far north as North Carolina’s Outer Banks. Fisher described the conditions as a rough beach week with high surf and a high risk of rip currents, advising people to stay out of the water through the weekend.

In Fort Lauderdale, Florida, drivers faced flooded streets when accessing the waterfront venues for the in-water boat show. The event is billed as the world’s largest of its kind. In Miami, Virginia Key recorded its highest king tide and its third-highest water level since records began three decades ago. Fisher stated that only hurricanes have produced higher water levels, marking a historical event from a king tide perspective.