Carlsbad's already-eroding shoreline faces a combination of beach loss, bluff collapse and coastal flooding this winter that could threaten homes, roads and public beaches, a Scripps Institution of Oceanography scientist warns.

Adam Young, a coastal geomorphologist at Scripps, described the danger as a "triple threat" in an Aug. 20 analysis published by the research center. Increased rainfall triggers landslides. Powerful waves accelerate erosion of beaches, sea cliffs and bluffs. And strong El Niño conditions can raise sea levels along the California coast by 6 to 12 inches, Young wrote.

"The first storm may strip all the sand off a beach, and without the natural sand buffer, the next storm can deliver a stronger punch," Young told AccuWeather on Sept. 17.

AccuWeather forecasters projected Super El Niño conditions would likely develop during the second half of the Atlantic hurricane season, potentially becoming one of the strongest on record.

The warning lands as Carlsbad is already dealing with serious coastal damage. The city declared a local emergency on Sept. 9, its fourth such declaration in 2026, to expedite bluff repairs along Carlsbad Boulevard. Crews began placing boulders weighing 4 to 8 tons on the beach north of the Encinas Creek outlet, extending an existing rock revetment 192 feet, the San Diego Union-Tribune reported. Small cracks had appeared in the pavement north of the existing 1,270-foot barrier.

City Manager Geoff Patnoe said in a Sept. 9 news release that the city takes a proactive approach to monitoring infrastructure ahead of storm seasons. The emergency declaration lets the city bypass the lengthy permitting process with agencies like the California Coastal Commission.

Tamarack State Beach has already been scoured to cobblestones. California State Parks closed the popular day-use parking lot on Aug. 28 after weeks of large waves stripped the shoreline bare. During high tides, waves were crashing onto the lot.

Young told the San Diego Union-Tribune on Sept. 4 that a mid-August survey showed swells had pushed sand from Tamarack to beaches in north Carlsbad and south Oceanside. He called the erosion signal "much stronger this summer" than in previous years.

San Diego City College professor Lisa Chaddock warned in a Sept. 22 Times of San Diego report that communities from Oceanside to Del Mar may see significant bluff damage and that cliff-top homes face danger this year.

More pressure is coming.

A Kelvin wave, a mass of warm water crossing the Pacific, was forecast as of mid-September to reach California in late September and could temporarily raise coastal water levels. Scripps physical oceanographer Mark Merrifield noted in the Aug. 20 analysis that the tidal cycle will peak around the end of 2026, with very strong king tides expected around Christmas that will combine with El Niño-elevated sea levels.

The Scripps California Mapping Program plans to survey the entire California coastline in fall 2026 and spring 2027 to measure how the coast responds. The California Coastal Commission is scheduled to vote Oct. 8 on Carlsbad's Local Coastal Program update, a decision that could affect whether open land near South Ponto Beach becomes a coastal park or 120 new townhomes.