This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: California's coastal bluffs and beaches look rugged, but they can be surprisingly fragile in the face of a powerful El Niño. The state saw that in 1982–83, when storms amid one of the most destructive El Niño winters in California history battered the coastline with powerful waves and torrential rain, leaving hundreds of millions of dollars in damage in its wake.
The storms coincided with elevated sea levels, high astronomical tides and very large waves delivered by repeated storms. Extreme waves that winter destroyed one-third of the Santa Monica Pier and tore off large sections of the Huntington Beach Pier and the Paradise Cove Pier, while also damaging the Seal Beach, San Clemente and Malibu piers. Numerous seawalls, decks and stairways were torn apart, and 33 oceanfront homes were destroyed.
Massive waves also stripped millions of cubic yards of sand from Southern California beaches, and sections of the Pacific Coast Highway suffered severe flooding, mudslides and washouts. Along the central coast, waves and high-tide flooding eroded bluffs. In Pacifica, just outside San Francisco, the edge of a sandy cliff lost over 65 feet (20 meters) as it failed, collapsing onto the beach and forcing the relocation of a two-story building and removal of an entire row of mobile homes.
This area of high but weak bluffs continued to erode over the subsequent decades, forcing the demolition of bluff-top homes and apartments. The El Niño now building in 2026–27 is forecast to be even stronger, and coastal homes are already seeing damage. I have studied coastal geology and oceanography in California for nearly six decades.
With the conditions expected this year, coastal flooding, coastal erosion and landslides are likely, and more dramatic cliff collapses wouldn't be a surprise, though every El Niño is different. El Niño is one end of a climate pattern that swings from warm to cold every few years and can change weather patterns around the world. Normally dry areas can experience flooding rains, and wet areas can suffer droughts.
Pacific Coast in particular can take a beating from powerful atmospheric river storms with heavy downpours. El Niños begin with a shift in wind patterns, which normally push warm waters from east to west along the equator. For reasons still not fully understood, the trade winds die and the warm pool of water in the western Pacific begins to flow back toward the coast of South America.
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