Storm to bring high surf, dangerous waves

The National Weather Service has issued a high-surf warning beginning Tuesday night and extending through Wednesday evening for the Bay Area, with an oncoming thunderstorm pushing dangerous conditions onto Bay Area beaches.

According to the warning issued Monday night, “A west swell with heights of 13 to 17 feet at 16 to 18 seconds will arrive late Tuesday and continue into Wednesday.

“This swell is expected to produce breaking waves along the shore of around 18 to 24 feet, with favored locations occasionally exceeding 27 feet.”

Conditions should persist from around 9 p.m. Tuesday night through 9 p.m. Wednesday and applies from Point Reyes in the north all the way down to the Big Sur region in the south, including the entirety of Ocean Beach.

A high surf warning means that “high surf will affect beaches, producing rip currents, localized beach erosion, and sneaker waves.”

As KQED warned in 2013, so-called “sneaker waves” or rogue waves may appear relatively small, but the speed with which waves approach the beach can injure beachgoers or sweep them away entirely.

Ocean Beach has one of the most dangerous riptides in the state. Drowning deaths are fairly rare, but in 2018 the U.S. Lifesaving Association (a non-profit group for lifeguards) declared the deadliest beach in California.

The latest Bay Area storm is what’s riling up the oceans, with a 90 percent chance of up to half an inch of rain and “possibly a thunderstorm” forecast for Tuesday night, according to the NWS forecast that accompanies the surf warning.

• SF High Surf Advisory [NWS]
• What Makes Sneaker Waves Dangerous [KQED]
• Hurricane Creates Deadly Ocean Beach Conditions [Curbed SF]
• SF Forecast [NWS]