SAN FRANCISCO—According to the National Weather Service, Bay Area beaches will experience hazardous weather conditions beginning at 10:00 a.m. Tuesday, January 12, and ending at 3:00 p.m. on Wednesday, January 13.

The affected areas are the San Francisco Peninsula Coast, San Francisco, Coastal North Bay including Point Reyes National Seashore, Southern Monterey Bay, and Big Sur Coast and Northern Monterey Bay.

The NWS said they expect these areas to experience “large breaking waves of 20 to 25 feet, locally up to 30 feet at favored breakpoints.”

These dangerous waves will increase the risk of strong rip currents, erosion around the coast, and King tides.

King tides are expected with waves of 20-30 feet, but the “Initial forerunners of 4 to 6 feet every 20 to 22 seconds will arrive Tuesday morning resulting in an increased risk for dangerous sneaker waves and rip currents,” the advisory stated.

Rip currents, the National Oceanic and Atmospheric Administration (NOAA) said, can move eight feet every second, which is quicker than Olympic swimmers. “Rip currents are powerful, narrow channels of fast-moving water that are prevalent along the East, Gulf, and West coasts of the United States. Panicked swimmers often try to counter a rip current by swimming straight back to shore—putting themselves at risk of drowning because of fatigue,” said NOAA.

NOAA said the rip currents occur even in good weather conditions, “You can have strong rip currents with sunny days and waves of only about two to three feet high. And the reason for that is that rip currents aren’t really caused by the weather. They’re caused by the waves and other factors like the tide and the shape of the bottom.”

Rip currents can be spotted by getting onto an elevated position, such as a dune line or beach access, “Start off by staying back from the water. Look for places where waves aren’t breaking, so flat spots in the line of breaking waves. And then also where there’s maybe foam or sediment in the water being transported away from the beach offshore,” said NOAA.

Officials warn residents to not go into the ocean or onto the beach until the hazardous weather has passed and to always check the local beach conditions before entering the ocean.

The NWS recommends that all inexperienced swimmers remain out of the ocean due to these dangerous weather conditions, do not be driving around the barricades or through the water with an unknown depth, and take precautionary actions to protect flood-prone property.