Low-lying waterfront areas across Southern Marin face minor tidal flooding through Tuesday, Oct. 13, under a Coastal Flood Advisory issued by the National Weather Service.
The advisory took effect at 9 a.m. Friday, Oct. 9, and runs through 3 p.m. Tuesday. The NWS warned that up to 1.4 feet of water above ground level is possible in low-lying areas near shorelines and tidal waterways along San Francisco Bay.
The Southern Marin Fire Protection District shared the warning on X on Friday, Oct. 9, urging residents to avoid flooded roads and use caution near shorelines.
Flooding of parking lots, parks and roads is expected, with isolated road closures possible. High tides will flood coastal trails and cut off access to some low-lying beaches.
Saturday peak
Saturday's tide will be the highest of the advisory period. The NWS forecasts a peak of 7.3 feet at the San Francisco tidal gauge at 11:50 a.m. Saturday, Oct. 10, measured relative to mean lower low water, a reference level based on low tides. That forecast already includes up to 1.2 feet of surge. High tide timing can vary up to 90 minutes along the bay shoreline.
El Niño-warmed ocean waters are contributing to the elevated tides. The San Francisco Chronicle reported that El Niño effects are adding about 9 inches to the gravitational tide, while long-term sea level rise has added roughly 3 more inches to the baseline set at the end of the 20th century.
What residents should do
The NWS advises residents to allow extra travel time, respect barricades, avoid driving through water of unknown depth and protect property vulnerable to flooding. Sandbag locations and preparedness resources are available on the district's website.
The NWS also issued a Beach Hazards Statement from Saturday morning through Monday afternoon, covering San Francisco, Northern Monterey Bay, and Southern Monterey Bay and Big Sur Coast, warning of breaking waves up to 16 feet, strong rip currents and sneaker waves. People visiting those ocean-coast areas should stay off jetties, piers and rocks and remain out of the water.
Updated forecasts are available from the NWS San Francisco Bay Area office.
