The surf was absolutely churning along the Bay Area coastline Thursday, forcing officials to extend a high surf advisory through the evening.
The advisory was originally set to end in the morning, but was revised to last through 9 p.m.
Emergency crews had their hands full due to the condition, including a dramatic rescue of a woman caught in the waves at Cowell Ranch State Park in Half Moon Bay.
The woman who had to be pulled out was walking along the beach with her dog and was too close to the water, officials said.
"You can tell it's actually churning out there. We've had sneaker waves. We've had rip tides. We've had reports of huge waves -- 25, even 30-feet high," said Cecile Juliette with San Mateo County Cal Fire.
The county incident command system proved crucial for the rescue. Harbor patrol, along with Coastside Fire, came in on the water.,Fire, sheriff and parks units observing from the land guided the water crews to the woman treading water 200 yards out.
"She was at the point of complete exhaustion," Deputy Harbormaster Jacob Walding said. "She started to go underwater. I dove in on top her, normally we try to stay on our machines, but I knew I didn't have time for another wave to hit her."
Officials said the woman is hospitalized in serious condition.
Crews were also called to rescue kayakers in Pacifica and a surfer at Mavericks.
Weather officials said during the high surf advisory, northwest swells ranged between 11 and 14 feet. Breaking waves were also expected to peak anywhere from 20 to 25 feet, possibly even higher at "favored locations."
Beaches facing to the west and northwest saw the largest waves, according to the weather service. South and southwest facing beaches saw "larger than normal waves."
The weather service warned beachgoers to watch out for strong rip currents, powerful waves in the surf zone and localized beach erosion.
"It is advised to stay off of rocks and jetties and never turn your back to the ocean!" the weather service tweeted.