El Niño Poses Flooding Threat to California Coast

The strengthening El Niño event this year is set to elevate sea levels along California’s coast, potentially causing widespread flooding. Experts are warning about the high sea levels and increased risk of disastrous weather impacts.

Record Sea Levels

California is bracing for potentially the highest sea levels recorded due to this El Niño. Mark Merrifield, director of the Center for Climate Change Impacts and Adaptation at UC San Diego, shared that sea levels might rise significantly above the average seasonal cycle by the fall and winter seasons. NASA’s satellite data already shows the eastern Pacific Ocean has risen over half a foot compared to the norm.

Effects of Warmer Waters

El Niño is linked to the displacement of colder surface water by warmer water, resulting in higher sea surface levels. These changes lead to greater risks including erosion, coastal narrowing, and waves moving landward. A loss of coastal buffer increases the possibility of flooding and cliff erosion. The risks are compounded by high tides and increased rainfall.

“High waves, high sea levels, high tides, and high rainfall will contribute to considerable coastal flooding,” said Merrifield.

Historical Precedents

Significant flooding occurred in areas like Ventura, Los Angeles, and San Diego counties in recent editions of El Niño. During these events, the entire California coast typically experiences higher waves as described by Merrifield. The San Francisco Bay Area has experienced notable peaks during past El Niño phases, as seen in 1982-83, 1997-98, and 2023-24.

Potential Rainfall Increase

El Niño could result in increased rainfall in Southern California, beginning late December through early March. Although the 2015-16 El Niño didn’t bring heavy rain to the area, the current El Niño is expected to shift these odds significantly. Forecasts suggest this could impact Northern California as well.

Daniel Swain, a UC climate scientist, highlighted the current unprecedented warmth of the eastern tropical Pacific Ocean, setting new records.

Impact on Marine Life

El Niño is expected to deepen marine heat waves off the coast, affecting ecosystems and potentially extending harmful conditions like the neurotoxin domoic acid, which impacts fishery seasons and wildlife.

The phenomenon also poses a threat to kelp habitats, further stressing marine life. Coastal areas are already experiencing uncharacteristically muggy weather due to the warmer ocean temperatures.

State officials, including state Sen. Mike McGuire, are working on monitoring these conditions, especially with regard to potential disruptions to fishery operations.