Environment & Science

King tides on Tuesday could bring 7-foot swells, possible flooding

File photo: During three winter months every year, the backbeat of California's coast changes. King Tides, the highest highs and lowest lows, offer a glimpse of sea level rise.
File photo: During three winter months every year, the backbeat of California's coast changes. King Tides, the highest highs and lowest lows, offer a glimpse of sea level rise.
Flickr via John Luton

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Exceptionally high tides are expected Tuesday as part of an annual tidal pattern known as king tides, forecasters say.

“We should probably look at potential for some low-lying flooding near the coastal areas this week,” said Eric Boldt, warning coordination meteorologist with the National Weather Service.

The increased water level could cause flooding in some parking lots as well as pooling on some beaches. 

Peak high tides occur every month during the full and new moons when the sun and moon align and their gravitational pulls cause higher-than-normal tides. King tides refer to the extra gravitational pull sun exerts as the Earth makes it closest approach to the sun during its yearly orbit.

That, combined with "the Blob" of unusually warm ocean waters and a storm system north of the region, could push tides above the predicted seven foot height.

“When the predicted height’s seven feet, you might expect to add a little more to that tide level — say maybe a half foot or so — and that’s when we start to see some problems,” Boldt said.

King tides are especially high as Earth approaches perihelion, the point in its orbit that it is closest to the sun. Perihelion will occur in early January.

Forecasters say king tides in December and January could be exacerbated by warmer El Niño water and storm surges. The prospects have increased the risk of coastal flooding in low-lying areas.

King tide dates in 2015-2016 (according to the California King Tides Project http://california.kingtides.net/):

L.A. County officials said they have been making preparations to handle the higher tidal surges.

“The county has been preparing for weeks now for the El Niño storms this winter combined with the possibility of strong tides at the same time,” said Carol Baker, a spokeswoman for the Los Angeles County Department of Beaches and Harbors.

Baker said 10-to-15-foot sand walls have been put in place to protect public buildings, such as lifeguard facilities and restrooms. She said additional sand berms have has been constructed at Zuma Beach, which might see flooding in parking lots and the promenade.

She added that extensive damage is not expected during the upcoming king tides.  

“In and of itself, the high tides, the damage they can do is fairly limited. We’re more concerned about a combination of high tide and a winter storm with heavy winds,” Baker said. “At this point, we don’t see that, because the weather looks pretty good this week.”

However, significantly more damage could occur if later king tides coincide with storms and cause powerful waves. Those could be on the horizon as a strong El Niño is expected to bring higher-than-average amounts of rain to Southern California.

“We expect most of the rain to come late December, January, February, March — that’s what’s being forecast,” Baker said. “The combination of a strong El Niño with winter storms and high tide is the thing that we are most concerned about and want to be prepared for.”