King tides have inundated streets and flooded homes and businesses along both U.S. coasts, impacting communities in California, Florida, and the Carolinas.
The phenomenon, which began earlier this week with the full moon, is expected to cause flooding in some areas into the weekend. King tides occur when the Earth, moon, and sun align gravitationally, and can happen multiple times a year.
This week's king tides have been intensified by additional factors. In Florida, strong high pressure to the north and low pressure over the Caribbean created increased swells, according to Chris Fisher, a National Weather Service meteorologist in Miami. Along the California coast, the ongoing El Niño has warmed ocean waters, increasing seawater volume. The occurrence of Kelvin waves, pulses of warm water that elevate sea levels, also contributed, said Roger Gass, a meteorologist with the weather service's Bay Area forecast office.
Residents in Southern California experienced the impact firsthand, with sandbags deployed in Huntington Beach and some resorting to paddleboards and surfboards to navigate flooded streets. Sections of the Pacific Coast Highway were closed, and tides were anticipated to reach near-record levels in Orange and San Diego counties. In Northern California, minor flooding was expected in low-lying coastal areas and tidal waterways during peak high tides, which were measuring approximately 1.9 feet above normal.
Most of Florida's Atlantic coast was under flood warnings through early Friday. Coastal cities in South Carolina, including Charleston and Myrtle Beach, also reported street flooding, with possible rip currents extending as far north as North Carolina's Outer Banks. "It’s been a rough beach week," Fisher noted, advising against entering the water due to high rip current risk and surf.
In Fort Lauderdale, Florida, the boat show, billed as the world's largest in-water exhibition, faced accessibility challenges due to flooded streets surrounding the waterfront venues. Virginia Key, a barrier island in Miami, recorded its highest king tide and the third-highest water level in three decades, with Fisher stating that only hurricanes had previously caused higher water levels in the area.