California weather officials have warned more than 3.3 million residents in the San Francisco Bay Area of potential road closures and travel disruptions due to coastal flooding on Monday.
The advisories are more common for 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 a “alignment of solar features” is contributing to Monday’s higher-than-normal tides.
Why It Matters
The coastal flood alert has a direct impact on millions of people who live and work along the Northern California coast, including heavily populated cities and transit routes. The NWS forecast predicted up to one foot of inundation above ground level 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.
What to Know
On Monday, NWS San Francisco issued a coastal flood advisory for the San Francisco Bay Area, warning that moderate flooding may affect over 3.3 million people in city coastline areas and nearby counties.
Residents and visitors to San Francisco, the North Bay Interior Valleys, and San Francisco Bay coastline areas were at risk of inundation from 7 p.m. to midnight PT, when tides surged above typical levels.
According to Behringer, most people will not notice the water changing unless they live near the coast in the affected areas. The last such alert was issued on June 26.
Minor coastal flooding was predicted during the advisory period, with “flooding of lots, parks, and roads, with only isolated road closures expected.”
The San Francisco tidal gauge predicted a high tide of 1.04 feet above average at 9:02 p.m. local time. Officials warned that high tide times could vary by up to two hours depending on where you are along the coast and in the bay.
The caution highlighted that even small flooding can be dangerous for drivers and property owners.
Residents in low-lying shoreline regions, including tidal creeks and waterfront neighborhoods, were advised to relocate vehicles and valuables to higher ground Monday evening.
What People are Saying
The NWS San Francisco coastal flood alert states, “If travel is required, allow extra time as some roads may be closed.” Avoid driving past obstacles or through water of unknown depth. Take the required steps to protect flood-prone properties.”
Small craft caution for the San Francisco Bay area: “Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in hazardous conditions.”
What Happens Next?
The caution will expire at midnight, but forecasters warned that coastal areas should be on the lookout for further flooding dangers, especially during high astronomical tides and after storms. Authorities regularly monitor flood risk and may issue more warnings when weather patterns shift or projections change.
Travelers, commuters, and businesses in the affected coastline counties should keep an eye out for updates from local authorities and the NWS regarding ongoing safety guidance and readiness warnings.
