A forecast for large swells along the San Mateo County and Central California Coast triggered the National Weather Service (NWS) to issue a high surf advisory.
The advisory, which warns of hazardous conditions and a "dangerous near shore environment," is scheduled to be in effect until 6 p.m. today.
Westerly swells are projected to be between 12 - 15 ft. with a period of 14 seconds between wave peaks, according to the NWS.
The agency also advised that local beaches could experience large breaking waves in excess of 20 ft.
Sneaker waves — large waves that can suddenly appear without notice — could also appear, according to the advisory. Steeper and west-facing beaches could also experience large breaking waves.
Area beaches should experience rip currents along with localized beach erosion, the agency said.