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Updated:August 10, 2026 2:15 pm PDT

Coastal Flood Advisory COASTAL FLOOD ADVISORY  
Napa County

  Effective: Sun, 8/9 9:43pm Severity: Minor
  Updated: August 10, 2026 2:15 pm Urgency: Expected
  Expires: Mon, 8/10 11:00pm Certainty: Likely

Areas Affected: San Francisco - North Bay Interior Valleys - San Francisco Bay Shoreline - Northern Monterey Bay - Southern Monterey Bay and Big Sur Coast
 
Alert Details:
* WHAT...Up to 1.6 ft of inundation above ground level is
possible in low-lying areas near shorelines and tidal
waterways.

* WHERE...Bayshore locations along the San Francisco Bay, San
Pablo Bay, and Monterey Bay.

* WHEN...Until 2 AM PDT Thursday.

* IMPACTS...Flooding of lots, parks, and roads with only
isolated road closures expected.

* ADDITIONAL DETAILS...At the San Francisco tidal gauge, high tide
is expected to be 1.6 ft above normal (7.46 ft MLLW) at 10:01 PM
Monday 8/10, 1.6 ft above normal (7.44 ft MLLW) at 10:57 PM
Tuesday 8/11, and 1.4 ft above normal (7.24 ft MLLW) at 11:49 PM
Wednesday 8/12. These predictions include both astronomical
tides and roughly 3-6 inches of additional water mainly from a
combination of thermal expansion and accumulated sea level rise
since the tidal datum was established (1983-2001). High tide
varies up to 90 minutes earlier or later along the Pacific Coast
and through the San Francisco Bay, respectively.

Information:
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.