Record 8-foot tides force extended flood warnings in SoCal

The National Weather Service extended flood advisories for all Southern California coastal counties through 2 p.m. Friday. This decision comes after unusually high tides brought seawater into low-lying areas in Newport Beach and Long Beach. The agency originally scheduled these alerts to expire at 1 p.m. Thursday. Devin Black, a meteorologist at the weather service’s Oxnard office, confirmed the extension. He noted that Orange and San Diego counties will be downgraded from severe flood warnings to coastal advisories through Friday afternoon.

The forecast timeline indicates that tides are expected to approach 8 feet on Thursday morning. Levels will then gradually subside into the weekend. Black reported that some tides this week broke records, describing them as being on the extreme end. While high tides affected the region broadly, he explained that the angle and magnitude of swells played a major role. San Diego and Orange counties faced higher risks because their geography is more exposed to southwesterly swells.

Impact has been concentrated in specific coastal zones. The Balboa area of Newport Beach experienced widespread flooding this week. Sunset Beach also suffered heavily, with several streets submerged and Pacific Coast Highway closed. Caltrans plans to close a portion of the highway again on Thursday. Long Beach has been a primary area of concern for weeks and was most acutely affected on Thursday. Black stated that the service has received reports of seawater over low-lying areas and shallow water reaching the base of some structures.

Looking ahead, coastal communities face a potentially long winter season. Higher tides are scheduled around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. If a strong storm arrives during these periods, flooding could become more severe. This scenario mirrors events from late January 1983, when a historic storm hit during a strong El Niño and high tides, damaging many piers along the California coast.

Scientists attribute the rising water levels to a mix of factors. Human-caused climate change is one element. An El Niño-fueled Kelvin wave has also brought warmer water from the equatorial Pacific along the coast. Additionally, a months-old marine heat wave unrelated to El Niño is influencing conditions. These events are converging with unusually warm waters to push tides higher than ever before. The combination is sending surges into beach cities like Newport Beach and Redondo Beach.

Mark Merrifield, director of UC San Diego’s Center for Climate Change Impacts and Adaptation, warned about these conditions during a town hall months ago. He predicted likely the highest sea levels ever recorded on the California coast associated with this El Niño. He stated that flooding along the Southern California coast was likely to be a major issue for the winter season. The current conditions align with those earlier predictions.

Ocean temperatures are being affected by multiple forces simultaneously. The marine heat wave is a key driver of the current surge. Scientists say this heat wave has caused seawater levels to rise 1.25 to 1.8 feet higher than they would from the movement of the moon, Earth, and sun alone. This additional rise is pushing water into areas that typically remain dry during normal tidal cycles.