San Diego coastline braced for heightened erosion and flooding as El Niño intensifies
Scientists and city officials warn that the upcoming Super El Niño could accelerate beach erosion, cliff collapse and coastal flooding along San Diego, prompting new resilience projects and additional surveys.
San Diego’s shoreline is preparing for a surge in erosion, cliff instability and flooding as forecasts indicate a strong El Niño event. Researchers say rising sea levels associated with the phenomenon could lift California’s coast by six to 13 inches, intensifying wave action that wears away beaches, sea cliffs and bluffs.
"Powerful waves can accelerate erosion of beaches, sea cliffs, and bluffs, and cause coastal flooding; and strong El Niño conditions can raise sea level on the California coast by six to 13 inches," said Adam Young, a researcher at Scripps Institution of Oceanography, UC San Diego.
"Combined, these factors increase coastal erosion and flooding during El Niño events, which can threaten public parks, beaches, critical infrastructure, highways, and homes," Young added.
The state’s California Coastline Survey has mapped the entire coast six times since 2023 and plans additional surveys in late 2026 and spring 2027 to quantify erosion from the upcoming event. San Diego’s City Council, which adopted a Coastal Resilience Master Plan in 2025, has identified several sites—including La Jolla Shores, Tourmaline Surf Park, Mission Beach, Ocean Beach and Sunset Cliffs—for mitigation work. City spokesperson Peter Kelly said design work has begun for projects at Tourmaline, Ocean Beach and Sunset Cliffs, while plans for La Jolla Shores and Mission Beach remain at the conceptual stage due to funding constraints.
The city is also installing sand berms at Mission Bay and other beaches to absorb surf energy. Experts note that erosion is already affecting areas from North County to the South Bay, with San Onofre State Beach experiencing sandstone loss that threatens Interstate 5. In Oceanside, beach retreat of up to 6.6 feet per year has required large-scale dredging projects.
"Any homes on the cliffs are going to be in danger this year," said Lisa Chaddock, a physical science professor at San Diego City College. She added that heavy rain and rising seas could exacerbate the South Bay sewage system, spreading pollution farther north.