Parts of the West Coast are facing an increased risk of coastal flooding this week as unusually high tides are expected to affect sections of California, Washington, and Oregon.
California’s Governor’s Office of Emergency Services (Cal OES) warned Wednesday that king tides are returning to the state, bringing with them high surf, dangerous rip currents, and the potential for minor to moderate coastal flooding in some locations.
According to Cal OES, the next surge of high surf and strong rip currents could push water levels up to two feet above normal at the San Francisco tidal gauge, based on National Weather Service (NWS) data. Low-lying areas near shorelines and tidal waterways may experience flooding through Sunday during periods of high tide.
Late Thursday, the NWS forecast office for the San Francisco Bay Area issued a coastal flood warning for the bay, citing the combined effects of king tides and storm surge. The agency cautioned that numerous roads could be closed and that low-lying properties—including homes, businesses, and critical infrastructure—may become inundated. Some shoreline erosion is also possible.
“Significant coastal flooding is expected due to high astronomical tides and storm surge,” the alert stated. “Up to 2.5 feet of inundation above ground level is possible in low-lying areas near shorelines and tidal waterways during the morning high tide Friday and Saturday.”
The coastal flood warning for the San Francisco Bay is in effect from 7 a.m. Friday to 2 p.m. PST Saturday, followed by a coastal flood advisory from 2 p.m. Saturday through 2 p.m. Sunday.
Beyond the bay area, a coastal flood advisory remains in place until 2 p.m. PST Sunday for the Pacific Coast from Sonoma County to Monterey County, including Monterey Bay. In those areas, forecasters expect flooding of parking lots, parks, and roads, along with potential road closures.
Residents are urged to plan for delays and avoid driving around barricades or through water of unknown depth. Officials also recommend taking steps to protect property that is vulnerable to flooding.
Cal OES shared several safety reminders for those in affected coastal regions:
- When in doubt, don’t go in.
- Keep children within easy reach.
- Monitor changing tides and weather conditions.
- Watch for unexpected large waves.
- Stay alert for floating debris.
The National Ocean Service defines king tides as a popular, non-scientific term used to describe exceptionally high tides.
Coastal flood warnings have also been issued in parts of Washington and Oregon. Along the Clatsop and Tillamook Coast and the South Washington Coast, warnings are in effect from 9 a.m. to 2 p.m. PST Friday. Additional warnings cover Coos Bay and surrounding estuaries from 8 a.m. Friday to 1 p.m. PST Saturday.
In these areas, the NWS said minor flooding is possible during high tides in low-lying zones near bays, sloughs, and the lower reaches of coastal rivers, with water levels potentially reaching up to one foot above ground level.
