Warm water and consistent big swells since June had begun to wash away the sand, he said. The damage was then compounded by Hurricane Marie over Labor Day weekend, leaving jagged boulders that formed a kind of cliff, just below fire rings that have played host to generations of teenage beach bonfires. The long-hidden ruins of a pier were visible under the waves.
“It’s just, the brunt of it,” Mr. Bond said, his voice trailing off.
The downtown of Laguna Beach lies at the mouth of a canyon, and many homes are perched on winding streets high above the beach. Dave Kiff, the city manager, said local officials were preparing not just for big waves, but also catastrophic flooding, landslides and even wildfires — all of which could be made worse by El Niño.
“We worry about all of that,” Mr. Kiff said.
Gary Griggs, a professor at the University of California, Santa Cruz, one of the state’s top experts on the coast, said that California’s shoreline was developed and hardened during a period of relative calm, from the 1940s to the 1970s, when beaches here were stable and wide.
Since then, the California coast’s median high tide line — which is where public property officially begins — has moved up only by the width of nickels. But, he said, extreme weather, including recent hurricanes in the Pacific, has amplified the effect of sea level rise, sending bigger waves during high tides.
It has been enough to squeeze many public beaches almost out of existence. While sea-level rise will be the big problem later in the century, the more immediate challenge will be “these short-term, extreme events, which California has experienced a number of times,” Dr. Griggs said.
