Record-breaking tides and coastal flooding are 'a preview' of what’s coming, scientists say

Record-breaking high tides rolled into Southern California waters for the second day in a row Tuesday.

The tide gauge in San Pedro read 8.18 feet Tuesday morning, its highest measurement since records began more than a century ago, after already setting a new record on Monday. The previous record of 7.93 feet was set in 2005.

Records were also broken at tide gauges in La Jolla and Santa Barbara.

High water levels spilled over seawalls and swept across beaches, inundating communities along L.A. and Orange County coasts that have been hit repeatedly by storm surges and destructive surf over the last few months.

“We've already seen impacts that we have not had in quite some time,” said Lisa Phillips, a meteorologist at the National Weather Service. 

The exceptionally high tides were expected to peak Tuesday and slowly subside as the week progresses. Coastal flood warnings are in effect up and down the coast until Thursday afternoon.

But scientists say the conditions are just a preview of what’s to come in the next few months with the highest astronomical tides of the year — and peak El Niño season — still on the horizon.

Coastal flooding

On the Balboa Peninsula in Newport Beach on Monday, water poured over the seawalls of some homes that back up to Newport Harbor, leaving up to a foot of flooding in some intersections.

At the corner of 39th Street and River Avenue, Diane Teitscheid waded ankle-deep, motioning for cars to slow down so as not to slosh the water into her and her neighbors’ garages.

“All the water on our entire street is coming from that house,” she said, pointing to a home where water rushed through the side gates.

The city urged residents to prepare for the high tides, knocking on doors and offering free sandbags at multiple locations. Some did not heed the warning.

“What we're finding is there's just some private residents that are choosing to do nothing,” said Joe Stapleton, the Newport Beach City Council member whose district includes the Balboa Peninsula. “And by doing nothing, they're intentionally flooding streets and neighbors' properties.”

Stapleton said the city is now planning to take “more of an enforcement approach,” which could include fines for people who refuse to bolster their seawalls with sandbags in flood-prone areas.

Several Newport Beach homes were inundated by seawater on Monday.

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Jill Replogle

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LAist

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Tide levels in some parts of Southern California set records Monday, when this photo was taken on Newport Beach's Balboa Peninsula, and again the following day.

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Jill Replogle

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LAist

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Flooding also prompted officials to shut down part of Pacific Coast Highway in Huntington Beach.

Farther north, seawater inundated streets and homes on the Long Beach Peninsula, where a number of structures along the boardwalk have been rendered uninhabitable by recent storm surges from Hurricane Marie and Tropical Storm Rachel.

What’s pushing the tides over the top?

Tides are naturally high during this time of year because of the position of the moon and sun.

But at the moment, other factors are driving up sea levels and pushing astronomical tides even higher than they would normally be.

First, the ocean off the coast of Southern California is warmer than ever recorded — we’re nearly a year and a half into a prolonged marine heat wave. Since warmer water takes up more space than colder water, sea levels are higher. Water temperatures across the Central Coast and Southern California are 5 to 9 degrees above average.

Roads and homes near 38th Street Park on Newport Beach's Balboa Peninsula flooded Monday.

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Jill Replogle

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LAist

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Scientists say the warming is being driven by a combination of human-caused climate change and El Niño, a climate pattern in which the normally cooler eastern Pacific Ocean heats up.

Second, El Niño has pushed a Kelvin wave into Southern California waters. What’s a Kelvin wave? It’s essentially a huge mass of warm water moving across the ocean. When a Kelvin wave collides with a landmass, it can raise sea levels up to a foot.

University of California climate scientist Daniel Swain also said the current tidal conditions are just the beginning of even more severe high tides over the next several months. That means more flooding for coastal communities.

“We have not seen the worst coastal flooding this year that we're likely to see later,” Swain said. “This is probably, unfortunately for those who are dealing with it, just a preview of what is to come. The coastal flooding will be more widespread geographically and probably significantly deeper later this season.”

Swain said king tides — the term for tides at their yearly peak — have yet to arrive. Tides generally don’t reach their highest until late November, December and January.

On top of that, Southern California will likely see continued sea level rise from El Niño-driven Kelvin waves over the next few months. And this year’s potentially historic El Niño season is also likely to come with significant rain, potentially adding storm surge and surf.