An extreme El Niño will unleash massive waves on the California coast

Key Points:

• California’s coast is expected to experience its highest waves in years this weekend, with breakers reaching up to 30 feet from Crescent City to Big Sur and potentially 50-foot waves at Mavericks near Half Moon Bay, prompting strong drowning warnings from the National Weather Service.
• These giant waves are linked to a strong El Niño event, which intensifies storms in the northern Pacific and increases wave power by about 32%, contributing to severe coastal erosion and beach shrinkage throughout the winter.
• Past strong El Niño events, such as in 2015-16, caused historic shoreline erosion and infrastructure damage, with this year’s El Niño predicted to be even stronger and more destructive, especially when combined with elevated tides.
• Coastal scientists warn that mitigation efforts like emergency armoring are temporary solutions, and critical infrastructure including Highway 1 and wastewater facilities near Ocean Beach face significant risks from storm-driven erosion and flooding.
• Researchers are closely monitoring beach changes in real time using drones and underwater mapping to better understand erosion processes during this El Niño, which serves as a preview of future coastal impacts expected from climate change-driven sea level rise.