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Officials are again asking millions in California to use caution when traveling on Tuesday night amid a coastal flood advisory that was issued for the region after a similar advisory was in place on Monday night.

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

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 stock image of the Golden Gate Bridge in San Francisco. A stock image of the Golden Gate Bridge in San Francisco. J Duquette/Getty

What To Know

The NWS reissued the coastal flood advisory Tuesday for San Francisco and surrounding areas, warning millions of potential travel disruptions and localized flooding due to unusually high tides. The advisory, which impacted the region Monday night, will remain in effect from 8 p.m. Tuesday to 1 a.m. Wednesday, covering San Francisco, North Bay Interior Valleys and the San Francisco Bay shoreline.

The NWS advisory issued Tuesday morning reaffirmed the risks of minor flooding. The highest tide expected at 9:57 p.m.—recorded at 1.11 feet above normal, at the San Francisco tidal gauge.

The tide will be slightly higher than on Monday, when the advisory warned that it was 1.04 feet above normal.

High-tide timing may vary by up to two hours elsewhere along the coast and throughout the Bay Area. Flooding is anticipated in low-lying areas near shorelines and tidal waterways. Residents and visitors are urged to allow extra time for travel, monitor road conditions and avoid any attempts to drive through flooded areas. Those in flood-prone locations should move vehicles, valuables and personal belongings to higher ground to minimize the risk of damage.

The coastal flood advisories are issued based on tide predictions, so it’s still not clear if the NWS will issue similar alerts later this week.

NWS meteorologist Lamont Bain told Newsweek that the advisory is for the areas immediately on the coast.

“This caliber of coastal flood is on the lower impact side, so coastal trails, parks down by the shore and any other infrastructure similar to that,” Bain said. “They will generally be impacted, but it’s pretty much confined.”

Bain added that the new advisory is technically an extension from the advisory issued on Monday night, but the office issued a new version.

What People Are Saying

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.”

NWS Bay Area, on X on Monday: “Larger than normal tidal swings will bring minor tidal flooding to the Bayshore over the next few evenings. Why? The combination of lunar perigee on July 20th and a new moon on July 24th.”

What Happens Next

The current advisory will expire at 1 a.m. Wednesday, but coastal communities are advised to stay vigilant beyond the warning period, especially during future high astronomical tides and after any storms.

Residents, travelers and businesses are encouraged to stay updated with official NWS communications and local authority advisories for the latest information and recommended safety measures.