The National Weather Service (NWS) has issued a Coastal Flood Advisory for Northern California because water levels along the coast are expected to be about 1 foot higher than normal in the coming days. The reasons are—
- Astronomical high tides
- Onshore winds (winds blowing from the sea toward the shore)
- Rough surf
- Persistently rising sea levels in recent days
Because of these factors, seawater can inundate coastal areas, low-lying regions, beach parking, coastal roads, and neighborhoods along the bay. This is not a major flood, but a Minor Flooding Advisory has been issued in light of the elevated conditions.
Coastal Flood Advisory is a warning issued when coastal water levels (tides, high waves, surf + ocean waves) are expected to rise above normal—potentially causing minor or nuisance coastal flooding.This warning is issued for situations where flooding is not fully dangerous, but there is a possibility of water filling lower-lying areas, coastal roads, parking lots/sidewalks, and shoreline areas.
According to the NWS, this level of flood typically involves an expected water rise of about 1–2 feet (roughly 30–60 cm).
This advisory targets coastal areas of Northern California, especially the San Francisco Bay and related bays/Monterey Bay coastal locations. According to the warning, water is likely to rise about 1 foot (roughly 30 cm) above ground—potentially affecting “low-lying areas near shorelines and tidal waterways.”
During high tide, when sea water is higher than normal, the risk of this type of flooding is greatest.The advisory remains in effect for the period when coastal waves, surf, tides, etc., combine to cause water to inundate coastal areas.
Affected areas/people
- Areas located along the coast: seaside, harbor edges, canals / tidal waterways, marshy/low-lying areas.
- Areas near roads, streets, parking lots, sidewalks, or parks where the sea level is slightly higher than usual.
- Beach, piers, jetties, coastal walkways, coves — where surf and waves can be stronger.
- Beaches, coastal shops, beach homes, coastal dwellings (cars, motorcycles) or their parking being in lower-lying areas.
Potential impacts
- Flooding of roads, parking lots, or coastal routes — some roads may be temporarily closed, or driving could be difficult.
- Risks to pedestrians or drivers from flooding — vehicles can get stranded, driving through water can be dangerous, and pedestrians may slip.
- Dangerous conditions at coastal shores, rocks, piers, and jetties due to waves or surf sudden high waves (sneaker waves), strong surf, and rip currents can make coastal areas hazardous.
- Coastal homes, shops, or land — if the ground is very low relative to the sea level, water may intrude portions of the land that are mostly below grade and could be damaged.
- Impacts on people’s safety and mobility — despite warnings, driving in unknown water or going near the shore can increase risk.
What precautions to take during Advisory — Safety tips:
If you are in areas near coastal or bay fronts, please follow these precautions:
- Avoid water-filled roads, coastal roads, and parking areas — if there is water on the road, do not drive a car or motorcycle; you can’t tell how deep the water is.
- Stay away from low-lying ground, the shoreline, piers, rocks, and jetties — strong surf or high waves can arrive suddenly.
- Park/place cars, bikes, and belongings in high or safe locations to prevent water damage.
- Be extra cautious at night — visibility is poor in the dark, making it hard to see water and waves.
- If possible, move a bit inland or to higher ground — especially if water is rising or warnings are issued.
- Check weather updates and follow alerts — regularly review information from the National Weather Service (NWS) or local authorities/weather services.
- Have essential supplies ready — such as a flashlight, mobile charger, emergency kit, water, and necessary medications — so you’re prepared if the situation worsens suddenly.
“It’s important to understand that a Coastal Flood Advisory is not a full-fledged warning. An Advisory means, ‘you may encounter minor flooding—take a little extra care. When there is a potential for moderate to major flooding—affecting homes, structures, infrastructure, and major roadways—NWS issues a ‘Coastal Flood Warning’ or a ‘Coastal Flood Watch’.
Therefore, an Advisory usually doesn’t pose a major danger to life and property, but for people in low-lying areas, coastal regions, and those living near the sea, taking precautions is very important.
Changing Challenges
- The sea level is rising gradually — because of this, high tides are no longer what they used to be. What was once extraordinary can now be common. As a result, the likelihood of flooding in coastal areas has increased.
- In gulf areas, waves, surf, storm winds, and tides are putting pressure on coastal regions even small “nuisance floods” are being affected.
- A need for better flood-mitigation planning — now, in many places, natural approaches such as wetland restoration and tidal marsh preservation are being recommended, in addition to traditional measures like cement barriers and roads, to reduce flood recurrence.
Conclusion
If you or people you know live in Northern California / the San Francisco Bay Area or other coastal bay areas, don’t take this Coastal Flood Advisory lightly. Even though it isn’t a “major flood warning,” you can still face road closures, flooding, sudden waves, and hazards along coastal edges.
So, be prepared—keep essential supplies on hand, park vehicles and valuables on higher ground, maintain some distance from the shore, and stay vigilant with weather updates and alerts.
