King Tides Flood Coastal Communities in California and Florida

Seawater flooded streets and entered homes and businesses in beach communities across California, Florida, and the Carolinas this week. The surge was driven by king tides that began with the full moon earlier this week and may continue to cause flooding through the weekend. These tides result from the gravitational pull and alignment of the Earth, moon, and sun, occurring several times a year over periods of several days.

Forecasters noted that additional factors amplified the impact this week. In Florida, strong high pressure to the north and low pressure over the Caribbean generated increased swells, according to Chris Fisher, a National Weather Service meteorologist in Miami. Along the California coast, the ongoing super El Niño has warmed the ocean, increasing the volume of seawater. Roger Gass, a meteorologist with the weather service's Bay Area forecast office in Monterey, identified Kelvin waves, which are pulses of warm water that lift sea levels, as another contributing factor.

In Southern California, residents in Huntington Beach placed sandbags outside homes on Wednesday to keep out floodwaters. Some locals used paddleboards and surfboards to navigate the streets. Stretches of the Pacific Coast Highway were closed, and tides were expected to approach record levels in Orange and San Diego counties. In the northern part of the state, minor flooding was expected through Saturday in low-lying areas along shorelines and tidal waterways during peak high tides.

Gass stated that coastal flooding generally occurred within one and a half hours before and after high tides. In Northern California, these tides peaked 1.9 feet above normal levels. Most of Florida’s Atlantic coast remained under flood warnings through early Friday. Street flooding was reported in South Carolina coastal cities, including Charleston and Myrtle Beach, while rip currents were possible as far north as North Carolina's Outer Banks.

Fisher described the conditions as a rough beach week, citing a high risk of rip currents and high surf. He advised residents to stay out of the water and away from the beaches through the weekend. In Fort Lauderdale, Florida, access to waterfront venues at the world’s largest-in-water boat show was difficult due to flooded streets near marinas, hotels, and convention centers.

Virginia Key, a barrier island in Miami, recorded its highest king tide and the third-highest water level since records began three decades ago. Fisher noted that water levels had only been higher during hurricanes. He called the event historical from a king tide perspective.