El Niño Is Flooding California's Coasts with the Highest Tides to Come

Record October high tides have already flooded parts of California’s coast, offering a warning of more severe inundation expected during the winter El Niño season. In Marin County, water reached about two feet on Shoreline Highway, while flooding spread from San Pablo Bay to Monterey and set a record for the highest Bay Area tide recorded in October. Drivers have been stranded in low-lying neighborhoods, and Newport Beach officials are distributing sandbags. The current flooding was driven by ordinary spring tides, which occur roughly twice a month; tide gauges showed water about a foot above normal. Researchers warn that winter storms arriving alongside annual “king tides” could bring substantially worse impacts.

UC Davis ecologist Fraser Shilling identifies six vulnerable areas, including San Francisco International Airport, coastal roads and beaches in San Luis Obispo County, Route 101 near Corte Madera, and Humboldt Bay. His analysis warns that once-in-a-century storms could raise water levels two to three feet above current levels, with flooding or levee failures near State Route 37 potentially causing $1.5 million in daily economic losses. Shilling says inadequate government action leaves communities exposed. Floodwaters also threaten electric vehicles and other lithium-ion battery devices: saltwater can damage batteries and trigger hard-to-control thermal runaway fires. Fire consultant Patrick Durham cautions that submersion is dangerous even in fresh water, and especially hazardous in saltwater, whose corrosive effects can compromise battery protections.