NOAA: Late‑October Event Set Record High Tides at Four California Gauges, Raising Flood Risk

NOAA says a late-October coastal event pushed California water levels to record highs at four tide gauges, bringing flooding and erosion concerns back into focus as another round of unusually high tides is forecast later this month and again in December. In a bulletin published Wednesday, NOAA’s Ocean Service said coastal water levels reached historic highs during Oct. 24-30, with impacts already including flooded roads, inundated homes and businesses, and disruptions to daily life.

The agency said four California locations recorded their highest observed water levels on record, measured above Mean Higher High Water, or MHHW, a NOAA tidal reference level based on the average of the higher of the two daily high tides and commonly used to describe coastal flooding thresholds. San Diego reached 2.80 feet above MHHW on Oct. 27, 2026; La Jolla reached 2.65 feet above MHHW; Los Angeles hit 2.70 feet above MHHW; and Santa Barbara reached 2.65 feet above MHHW. “NOAA’s tide gauge at San Diego, California, captured its highest water level on record, 2.80 feet above Mean Higher High Water (MHHW) on October 27, 2026,” the bulletin said. NOAA also reported that Santa Monica reached 2.72 feet above MHHW, its second-highest reading on record; Port San Luis hit 2.35 feet above MHHW, its fourth-highest; and Monterey reached 2.20 feet above MHHW, its seventh-highest.

NOAA attributed the event to a rare mix of factors that raised sea levels along the coast at the same time. One was a perigean spring tide, an astronomical setup that can produce higher-than-normal high tides when the moon is closer to Earth and tidal forces are stronger. NOAA also pointed to El Niño-driven, coastally trapped Kelvin waves, which can push warm water eastward and raise sea level by several inches along the West Coast. An ongoing marine heatwave added to the effect, the agency said, because warmer water expands and lifts sea levels. The measurements come from NOAA’s federal CO-OPS tide-gauge network.

The timing matters because California is already in a strong 2026-27 El Niño pattern that forecasters have linked to elevated West Coast sea levels. NOAA’s warning is practical as much as scientific: Even without a major storm, unusually high tides can worsen flooding and coastal erosion in low-lying areas. That risk was evident during the late-October event, when the agency said communities dealt with flooded roads, water entering homes and businesses, and broader disruptions to everyday routines.

NOAA said above-normal high tides are forecast again for Nov. 22-27 and Dec. 22-26, and warned that flood risk could climb further if storms arrive or Kelvin waves continue. The agency directed residents and local officials to its Monthly High Tide Flooding Outlook and Coastal Inundation Dashboard for day-by-day monitoring. The new warning also comes after Gov. Gavin Newsom proclaimed a state of emergency on Sept. 21 to strengthen statewide El Niño preparedness. As California heads into another stretch of elevated tides, NOAA’s latest records suggest the coast may remain vulnerable even before winter storms fully arrive.