Weather Service extends flood alerts for SoCal coast as tides peak at 8 feet

The National Weather Service extended flood advisories for all Southern California coastal counties through 2 p.m. Friday on Wednesday. The alerts were originally set to expire at 1 p.m. Thursday. Devin Black, a meteorologist for the service’s Oxnard office, confirmed the change. Orange and San Diego counties, which faced a more severe flood warning until Thursday afternoon, will now remain under a coastal advisory through Friday afternoon.

High tides have already inundated low-lying areas in cities including Newport Beach and Long Beach. Black reported that officials observed seawater covering low-lying zones. In some instances, shallow water reached the base of structures. Tides are forecast to approach 8 feet Thursday morning before gradually subsiding into the weekend. Black described recent tides as being on the extreme end of historical records.

The Balboa area of Newport Beach has seen widespread flooding this week. Sunset Beach is another hard-hit zone where several streets are flooded. Pacific Coast Highway is closed in that area. Caltrans plans to close a portion of PCH on Thursday as well. Long Beach has been the primary area of concern for weeks, according to Black. He noted that while tides were high regionally, the angle and magnitude of swells played a major role. San Diego and Orange counties faced higher risks due to their exposure to southwesterly swells.

Scientists attribute the elevated water levels to a mix of factors. Human-caused climate change has impacted ocean temperatures. An El Niño-fueled Kelvin wave brings warmer water from the equatorial Pacific up and down the coast. A separate marine heat wave, unrelated to El Niño, has persisted for months. This heat wave has caused seawater levels to rise 1.25 to 1.8 feet higher than levels driven solely by the movement of the moon, Earth, and sun.

Mark Merrifield, director of UC San Diego’s Center for Climate Change Impacts and Adaptation, warned of these conditions months ago. During a town hall, he predicted likely the highest sea levels ever recorded on the California coast associated with this event. He stated that flooding along the Southern California coast would likely be a major issue for the winter season. The current situation aligns with that forecast as surges push water into beach cities like Newport Beach and Redondo Beach.

Higher tides are expected around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. If a strong storm arrives during those periods, it could result in more severe flooding. A similar event occurred during the historic storm of late January 1983. That storm hit during one of the strongest El Niños on record and damaged many piers along the coast. The storm arrived at a time when tides were already very high.