The Southern California coast is bracing for multiple days of flooding this week, with near-record or record-high sea levels anticipated to impact low-lying areas. The inundation began Monday morning with high tide and is expected to continue through Thursday afternoon, according to warnings from the National Weather Service.
Officials in coastal cities like Newport Beach and Long Beach have been actively preparing for the surge. Crews are moving sand to shore up beaches, installing sandbags, and working to protect areas that have seen damage in recent months, such as the Balboa Peninsula and the Long Beach Peninsula. City officials urged residents in flood-prone zones to “take precautions now,” which includes moving vehicles to higher ground and protecting property with sandbags. The National Weather Service warned that seawater levels could reach near-record or record heights across the region, with the highest high tides expected Monday, Tuesday, and Wednesday mornings.
Orange and San Diego counties are identified as the areas at highest risk, where the National Weather Service has issued a coastal flood warning lasting until Thursday afternoon. Further north, in Los Angeles, Ventura, Santa Barbara, and San Luis Obispo counties, a coastal flood advisory was put in place. The weather service stated that significant coastal flooding is expected, noting that low-lying property, including homes, businesses, and some critical infrastructure, would be inundated, and some shoreline erosion would occur in the morning hours. The weather service also noted that isolated damage to structures was possible in the most vulnerable areas due to seawater inundation. Long Beach's breakwater, while protecting from western waves, leaves a narrow stretch of the peninsula vulnerable to southern swells, an area that has already sustained damage this year.
This year's damaging swells are the result of a rare combination of threats. An active eastern Pacific hurricane season, fueled by El Niño, is one factor. Another is a marine heat wave. Added to these is an astronomical alignment that occurs only once every two decades. Scientists also point to record-hot ocean water temperatures off California as a contributor, causing seawater levels to be between 1.25 to 1.8 feet higher than what would be expected from the movement of the moon, Earth, and sun alone. This phenomenon is further influenced by an El Niño-fueled Kelvin wave and a months-old marine heat wave that is separate from El Niño.
Total water levels in Los Angeles, Orange, and San Diego counties could exceed 8 feet above the established baseline, which represents the average daily lowest water level observed between 1983 and 2001. Specific projections highlight the severity:
In Newport Beach, seawater levels already reached 8 feet on Sunday, 1.8 feet higher than the expected high tide alone, according to city officials. Projections for the city's coastline anticipate levels could reach 8.3 feet on Monday around 9:15 a.m., and an even higher 8.5 feet on Tuesday at 9:50 a.m. and Wednesday at 10:28 a.m.
At Los Angeles Harbor, the highest-ever seawater level was 7.92 feet, recorded on January 10, 2005, during a weak El Niño. On Sunday, the preliminary level hit 7.71 feet. The National Weather Service office in Oxnard projects levels could reach 8.1 feet on Tuesday and 8 feet on Monday and Wednesday.
La Jolla's record for highest seawater level stands at 7.81 feet, set on November 25, 2015, during the last “very strong” El Niño, as reported by the weather service's San Diego office. Sunday saw levels reaching 7.66 feet there.
Looking ahead, scientists warn that coastal flooding is expected to intensify later this year and into next. Even higher tides, known as king tides, are anticipated around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. These upcoming king tides are expected to be exceptionally extreme due to astronomical factors, specifically the proximity to the peaks of the 18.6-year lunar node tidal cycle and the 4.4-year lunar perigee tidal cycle, which affect tide-generating forces, according to Reinhard Flick, a researcher at the Scripps Institution of Oceanography at UC San Diego. Should significant storms coincide with these king tide events, scientists caution that the coastal flooding risk would be further exacerbated. Separately, experts are also tracking a marine heat wave of 2026, which is “simmering” in the Pacific Ocean off California's coast and could lead to a warm, humid, and stormy summer. Surface temperatures at Scripps Pier in La Jolla, for instance, reached around 77 degrees in early August, well above the average maximum of 70 degrees, and were still around 73 degrees on Thursday, significantly higher than the typical 66 degrees for this time of year.
