Santa Monica beachgoers and pier visitors face minor flooding through Thursday night as astronomical high tides push seawater into low-lying coastal areas, parking lots and walkways.

The National Weather Service's Los Angeles/Oxnard office issued a Coastal Flood Advisory covering Los Angeles County beaches, including Santa Monica, that remains in effect through midnight Thursday, Aug. 13. The advisory was first issued at 8:58 p.m. Monday, Aug. 10.

Flooding will peak each evening between 8 p.m. and 10 p.m. as tides reach 7.3 to 7.5 feet, according to the advisory. No structural damage is expected.

The NWS described the situation as "minor flooding of normally dry harbor and sandy beach areas," and advised residents to protect flood-prone property and not drive around barricades or through water of unknown depth.

Separately, KTLA reported Tuesday, Aug. 11, that Metrolink service was suspended in Orange County as tides rose, a sign the high water is already disrupting infrastructure across the region. No Santa Monica-specific transit or infrastructure disruptions have been confirmed.

Cooler temperatures, possible thunderstorms

The high tides arrive alongside an unusual mid-August cooldown. Temperatures on Tuesday were forecast at 2 to 6 degrees below normal for mountain and valley communities, and the NWS expects Wednesday highs to land 5 to 10 degrees below normal across much of the region. Strong onshore flow is keeping a thick marine layer over coastal areas, and some Santa Monica beaches may stay cloudy all day through Thursday.

The NWS also warned of isolated thunderstorms through Wednesday night, though the highest risk sits in the Antelope Valley and interior mountain communities rather than at the coast. Isolated wind gusts could reach 50 mph in mountain areas, and lightning could spark fires.

Different hazard from late July

This weather pattern is distinct from the high surf advisory Santa Monica experienced in late July, when Hurricane Genevieve drove dangerous waves and rip currents to local beaches. That event paired with extreme heat. This week's combination of coastal flooding, below-normal temperatures and persistent cloud cover presents a different set of risks for residents near the water.

What residents should know

  • The Coastal Flood Advisory expires midnight Thursday, Aug. 13.
  • Peak flooding: 8 p.m. to 10 p.m. each evening.
  • Tides reaching 7.3 to 7.5 feet.
  • Vulnerable areas: parking lots, beaches, walkways and low-lying coastal zones.
  • Do not drive around barricades or through standing water.

The Santa Monica Fire Department and LA County Lifeguards have not issued public statements specific to this advisory.