Tides Reach 8 Feet as El Nino Floods SoCal Coast

Tides are set to reach 8 feet Thursday morning along the Southern California coast, a level that has already triggered widespread flooding in low-lying areas. The National Weather Service extended flood advisories for all coastal counties through 2 p.m. Friday, a change from the original expiration time of 1 p.m. Thursday. Devin Black, a meteorologist for the service’s Oxnard office, confirmed the extension.

Orange and San Diego counties, which faced a severe flood warning through Thursday afternoon, will be downgraded to a coastal advisory through Friday afternoon. Black noted that the service has received reports of seawater covering low-lying areas, with some structures experiencing shallow water at their bases. He stated that this week’s tides were definitely on the extreme end and broke records.

The Balboa area of Newport Beach has suffered widespread flooding this week. In Sunset Beach, several streets are flooded, and Pacific Coast Highway is currently closed. Caltrans plans to close a portion of PCH for part of Thursday. Long Beach has been the most acutely affected area for weeks, according to Black. He explained that while tides were high regionally, the angle and magnitude of the swells made the risk higher for San Diego and Orange counties, which are more exposed to a southwesterly swell.

Scientists indicate that this flooding is the result of a mix of astronomical and tidal events converging with unusually warm waters off the coast. Ocean temperatures have been affected by human-caused climate change, an El Nino-fueled Kelvin wave bringing warm water from the equatorial Pacific, and a months-old marine heat wave unrelated to El Nino. This marine heat wave has pushed seawater levels 1.25 to 1.8 feet higher than they would be from the movement of the moon, Earth, and sun alone.

Mark Merrifield, director of UC San Diego’s Center for Climate Change Impacts and Adaptation, warned at a previous town hall that he expected likely the highest sea levels ever recorded on the California coast associated with this event. He stated that flooding along the Southern California coast is likely to be a major issue for the winter season. He referred to the strengthening El Nino conditions driving these changes.

Higher tides are expected around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. If a strong storm arrives during those periods, it could result in even more severe flooding. A similar event occurred during the historic storm of late January 1983, which hit during one of the strongest El Ninos on record and damaged many piers along the California coast. That storm arrived at a time when tides were very high, compounding the damage.