La côte de la Californie est prête pour les marées. C'est là que les impacts seront les plus importants

Coastal communities in Southern California are preparing for further flooding on Thursday and Friday as El Niño conditions maintain exceptionally high water levels. The National Weather Service extended flood advisories for all coastal counties in the region through 2 p.m. on Friday. This extension follows initial alerts that were scheduled to expire at 1 p.m. on Thursday. Meteorologist Devin Black from the agency’s Oxnard office confirmed the prolonged duration of the threat. Orange and San Diego counties, which faced more severe flood warnings through Thursday afternoon, will transition to a standard coastal advisory through Friday afternoon. Reports indicate seawater has covered low-lying areas, with some structures experiencing shallow water accumulation at their bases. The Balboa area of Newport Beach has suffered widespread inundation this week. In Sunset Beach, multiple streets remain flooded, forcing the closure of Pacific Coast Highway. Caltrans intends to keep portions of the highway closed on Thursday as well. Long Beach emerged as the most critically affected location on Thursday, having been a primary area of concern for weeks. Tides are projected to peak near eight feet on Thursday morning before gradually decreasing over the weekend. Several tidal measurements this week surpassed historical benchmarks. Black described the levels as being on the extreme end of the scale. Record-breaking heights were documented across multiple monitoring stations. The tide gauge in San Pedro, located in Los Angeles Harbor, registered a height of 8.19 feet on Tuesday. This measurement stands as the highest level recorded since data collection began in November 1923. In Santa Barbara, high tide reached a record 8.04 feet on Tuesday before dropping slightly on Wednesday. Ryan Kittell, another meteorologist for the National Weather Service, noted that the tide in La Jolla hit 7.98 feet on Tuesday, surpassing the previous record of 7.83 feet set in November 2015. At the San Diego station, Tuesday’s high tide measured 8.52 feet, eclipsing the prior record of 8.26 feet established earlier in July. Kittell stated that while Tuesday marked the peak, Wednesday’s levels were similar but slightly lower, with a general decline expected throughout the week. Uncertainty persists regarding future tidal extremes. It is not yet clear if upcoming winter king tides will exceed these new records. Scientists emphasize that ocean temperature changes stem from a combination of factors. These include human-induced climate change, an El Niño-driven Kelvin wave transporting warm water from the equatorial Pacific along the Americas, and a separate marine heat wave lasting several months. Although tides were elevated regionally, Black explained that the angle and magnitude of swells significantly influence local risks. San Diego and Orange counties faced heightened danger because their geography offers greater exposure to southwesterly swells. Earlier in the cycle, officials and residents braced for impacts following early-season storms that had already caused substantial damage. Flood warnings for Orange and San Diego counties were active from Sunday morning through midday Thursday. Morning high tides in those areas ran one to 1.7 feet above projections. The weather service warned that numerous roads might close and that low-lying properties, including homes, businesses, and critical infrastructure, would face inundation. Metrolink suspended service in southern Orange County from Monday through Friday at the Laguna Niguel/Mission Viejo and Oceanside stations due to the tides. This rail line, utilized by both Metrolink and Amtrak connections between Orange County and San Diego, has long faced threats from coastal erosion and had previously closed for several days during the summer. Infrastructure repairs are underway elsewhere. The California Department of Transportation secured millions of dollars in emergency funds to fix a massive crack that formed during early October high tides. The damage occurred on a slope beneath Pacific Coast Highway near Laguna Beach, specifically near the Moro Beach section of Crystal Cove. In coastal regions of Los Angeles, Ventura, Santa Barbara, and San Luis Obispo counties, the weather service issued lower-level flood advisories. Peak tides occurring on Monday, Tuesday, and Wednesday mornings reached 7.5 to 8 feet, exceeding astronomical projections by one to 1.5 feet. Newport Beach City Manager Seimone Jurjis stated that city teams have been actively reinforcing sand berms, evaluating vulnerable seawalls, placing sandbags, and inspecting storm drains. The department is also preparing additional pumps, heavy equipment, and emergency resources while coordinating extra staff across departments to monitor conditions. The city offered sandbags at three locations and urged residents with private seawalls to reinforce them if necessary. Viral videos circulating online show waves striking oceanside homes, parking lots, boardwalks, and jetties in Long Beach and Newport Beach. Looking ahead, this period may signal the start of a prolonged winter season. Higher tides are anticipated around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. A strong storm coinciding with these periods could trigger even more severe flooding. Similar conditions occurred during the historic storm of late January 1983, which struck during one of the strongest El Niños on record. That event damaged many piers along the California coast when a powerful storm met extremely high tides. Mark Merrifield, director of UC San Diego’s Center for Climate Change Impacts and Adaptation, had predicted these outcomes months earlier. During a town hall, he warned of likely the highest sea levels ever recorded on the California coast associated with the strengthening El Niño, noting that flooding along the Southern California coast would become a major issue for the winter season.