Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.

Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content.

Weather officials in California are warning more than 3.3 million people in the San Francisco Bay Area about potential road closures and travel complications amid coastal flooding on Monday.

The advisories are more common with king tides, which are exceptionally high tides that typically occur during the winter months, but National Weather Service (NWS) meteorologist Dalton Behringer told Newsweek that an “alignment of solar features” is contributing to higher-than-normal tides on Monday.

Why It Matters

The coastal flood advisory directly impacts millions living and working along the Northern California coast, including densely populated urban areas and travel corridors. According to the NWS forecast, up to one foot of inundation above ground level was possible in low-lying areas near shorelines and tidal waterways, including parks, parking lots and roads, prompting officials to warn of isolated road closures and potential disruptions to evening travel and property safety.

A boater launches his boat into San Francisco Bay by the Golden Gate Bridge on March 21, 2025, in Sausalito, California. A boater launches his boat into San Francisco Bay by the Golden Gate Bridge on March 21, 2025, in Sausalito, California. Justin Sullivan/Getty

What To Know

NWS San Francisco issued a coastal flood advisory for the San Francisco Bay Area on Monday, warning that more than 3.3 million people could be affected by minor flooding in city shoreline communities and surrounding counties.

From 7 p.m. to midnight PT, residents and travelers in San Francisco, the North Bay Interior Valleys and San Francisco Bay shoreline communities faced increased risk of inundation as tides rose above average levels.

Behringer said most people won’t notice the water changing unless they live near the coast in the affected areas. The last time such an advisory was issued was June 26.

Minor coastal flooding was expected during the advisory period, with “flooding of lots, parks, and roads with only isolated road closures expected.”

At the San Francisco tidal gauge, high tide was forecast to reach 1.04 feet above normal at 9:02 p.m. local time. Officials cautioned that high tide timing could vary by up to two hours depending on the location along the coast and around the bay.

The advisory emphasized that even minor flooding can pose hazards for motorists and property owners.

Residents in low-lying shoreline areas—including tidal creeks and waterfront neighborhoods—were advised to move vehicles and valuables to higher ground Monday evening.

What People Are Saying

The NWS San Francisco coastal flood advisory: “If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property.”

Small craft advisory for the San Francisco Bay area: “Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in hazardous conditions.”

What Happens Next

The advisory will expire at midnight, but forecasters noted that coastal communities should remain vigilant for additional flooding threats, particularly during periods of high astronomical tides and following storm events. Authorities routinely assess flood risk and may issue further warnings as weather patterns evolve or forecasts change.

Travelers, commuters and businesses across the affected shoreline counties are advised to monitor updates from local authorities and the NWS for continued safety guidance and preparedness messages.