High tides could flood California and Florida on Thanksgiving

The next round of major tides during Thanksgiving week could bring more flooding along the California and Florida coasts, and the super El Niño could perpetuate that threat into the winter.

Final round of records

King tides are the highest high tides in a year, triggered by gravitational pull when the Moon, Sun and Earth align.

(WATCH: King tides explained)

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October king tides bring record flood levels to many locations in Southern California, including Los Angeles and San Diego, inundating roads, buildings and restaurants on oceanfront properties.

These West Coast king tides were spurred by a slow movement of warm water pushed against the coast, called an El Niño-spawned Kelvin wave atop already record ocean water near the California coast.

In South Florida, Virginia Key, near Miami, experienced moderate flooding during a record 10-day stretch, with water levels higher than during Hurricanes Irma or Wilma.

(MORE: Impacts of October flooding in Florida and California)

Holiday Concerns

The next king tides will arrive during Thanksgiving week, when the next full moon occurs.

West Coast

Along the west coast, flooding could be worse than what we just saw.

“In California, tides will be about a half foot higher than the October highs,” physical oceanographer Greg Dusek told Weather.com.

“This means that even if El Niño does not increase water levels further, there will be significant flooding along the California coast,” Dusek said.

As shown in the chart below from Dusek’s Coastal Water Level Dashboard, additional mainstide flooding is likely in California and parts of the West Coast, again during Christmas week and then again in late January.

The highest king tides of the year along the west coast generally occur around the winter and summer solstices.

Florida, Southeast

Subtracting any possible influence from winds or storms, which we’ll talk about later, Dusek predicted that the highest tides in the southeastern United States in November would be similar to what just happened.

Brian McNoldy, a scientist at the University of Miami, pointed out in a Bluesky article that ocean water levels along the South Florida coast are typically highest in October, due not only to tides, but also ocean heat and weather conditions typical for that time of year.

Ultimately, there is another significant threat of tidal flooding during Thanksgiving week along the Southeast coast, including Florida’s Atlantic beaches.

A big joker

There is one factor that can significantly increase coastal flooding during a king tide.

Namely the weather.

“If there are storms, or even onshore winds, additional flooding is likely to occur,” Dusek said.

In late October, strong and persistent onshore winds worsened flooding along Florida’s Atlantic coast.

And what is likely the strongest modern El Niño on record will not only keep ocean water near California much warmer than usual, but also boost the southern jet stream through spring.

This increases the risk of strong Pacific storms rolling into California with breaking waves, heavy rain and winds. This also increases the risk of more favorable storm tracks for southeastern coastal flooding.

It is far too early to tell whether one or more storms could move in or develop during upcoming main tides, but if such a storm occurs during the week of Thanksgiving or Christmas, it could only increase the impacts of coastal flooding from main tides.

If you live in or pass through one of these areas affected by flooding in recent days, prepare for further coastal flooding in the coming months.

Jonathan Erdman is a senior meteorologist at Weather.com and has covered national and international weather since 1996. Extreme and bizarre weather are his favorite topics. Contact him on Blue sky, X (formerly Twitter) And Facebook.