Stronger Storms, Higher Seas, And Greater Flooding Risks Could Threaten California This Winter

BAY AREA, CA — As towering waves pound California's coastline, floodwaters overtop rivers, and powerful winter storms batter communities, residents should prepare now for what experts say could become one of the strongest El Niño events on record.

That was the message Tuesday from climate scientists, meteorologists, and emergency management officials during the "Super El Niño Town Hall," hosted by California Sen. Mike McGuire, who represents the North Coast and North Bay in the California Senate.

The take-away: Prepare now for the strongest El Niño events on record, warning that higher sea levels, powerful storms, coastal flooding, and heavier winter rainfall could combine to create widespread impacts across the Golden State.

Climate scientist Daniel Swain said ocean temperatures in the eastern tropical Pacific have already reached record levels for this time of year and continue to climb. Forecast models indicate the event could rival or exceed any El Niño recorded during the modern era, although California's exact rainfall totals remain uncertain.

Scripps Institution of Oceanography Director Mark Merrifield said California should expect sea levels to rise well above normal this fall and winter. He said higher ocean levels, king tides, large waves, and heavy rainfall could combine to produce extensive coastal flooding, beach erosion, saltwater intrusion, and damage to shoreline infrastructure.

Merrifield said the state could experience the highest sea levels ever recorded along California's coast because El Niño will add to the long-term rise already caused by climate change.

Swain said El Niño remains a naturally occurring climate cycle, but human-caused climate change raises global ocean temperatures and increases the potential for more extreme weather impacts. He said the combination of long-term warming and an exceptionally strong El Niño could increase the likelihood of intense winter storms and flooding across California.

The scientists said the greatest impacts are most likely between late December and March, rather than during the early part of the rainy season. Swain said strong El Niño events often produce back-to-back storms that keep the Pacific storm track aimed at California for extended periods.

KTVU Chief Meteorologist Mark Tamayo said above-average precipitation appears increasingly likely, but warmer storms could push Sierra snow levels higher, causing more rain and increasing flood risks instead of building mountain snowpack.

Tamayo also warned that tropical moisture, warmer Pacific waters, and increased atmospheric instability could elevate wildfire risks before winter if dry lightning develops during the fall fire season.

California Office of Emergency Services Assistant Director Nate Ortiz said state agencies have already increased planning efforts by coordinating with local governments, the National Weather Service, the Department of Water Resources, Caltrans, the California Highway Patrol, CAL FIRE, the National Guard, and other emergency response agencies. Officials also plan to pre-position equipment and personnel before major storms arrive.

Ortiz urged Californians to sign up for local emergency alerts, assemble emergency supply kits, secure important documents, prepare evacuation plans, keep vehicles fueled or charged, and stock enough food and water to remain self-sufficient for at least 72 hours.

The panel also warned that warmer ocean temperatures could stress marine ecosystems by suppressing nutrient-rich upwelling, increasing harmful algal blooms, damaging kelp forests, and shifting fish populations farther north.

Despite the warnings, the experts emphasized that the purpose of the town hall was preparation rather than alarm. Swain said California still has several months to reduce risks before the most dangerous conditions could develop this winter.

McGuire respresents the 2nd District, which covers Del Norte, Trinity, Humboldt, Lake, Mendocino, Sonoma, and Marin counties. He is a candidate for California's 1st Congressional District.