Record-Warm Ocean and a Rare Lunar Alignment Set Up Possible Record Tides Along California’s Coast

LOS ANGELES, Oct. 25 (TodayViralUSA) — California is bracing for a week of exceptionally high tides that forecasters say could set modern records in San Diego and Los Angeles, as unusually warm ocean water and a rare alignment of the moon combine to push the sea higher than official tide tables predict.

The National Weather Service issued a coastal flood warning running from Sunday morning through Thursday afternoon for coastal San Diego and Orange counties, where it expects “significant coastal flooding” that could inundate low-lying homes, businesses and critical infrastructure. Advisories cover Los Angeles, Ventura, Santa Barbara and San Luis Obispo counties, as well as the San Francisco and Monterey bays.

Why the water is so high

The main driver is heat. Warm water expands, and the ocean off California has been running far hotter than normal, fed by a long-running marine heat wave and by warmer water moving north from the El Niño developing off Peru. The weather service says tides in Southern California are running 1.25 to 1.75 feet above astronomical predictions as a result, the Los Angeles Times reported.

“As far as I know, this is unprecedented, especially for this length of time,” Reinhard Flick, a researcher at the Scripps Institution of Oceanography, told the Times, noting that water levels have been at least half a foot above predictions for months.

Astronomy is adding to the problem. The coast is near the peaks of two long tidal cycles, the 18.6-year lunar nodal cycle and the 4.4-year lunar perigee cycle, which slightly strengthen the moon’s tide-raising pull. Over the longer term, sea levels along the California coast have risen by about a foot over the past 125 years.

Total water levels in Los Angeles, Orange and San Diego counties could reach 7.5 to 8 feet above the baseline used by forecasters. National Weather Service meteorologist Philip Gonsalves told the San Francisco Chronicle that San Diego and Los Angeles will “more likely than not” see their highest recorded tide levels on Tuesday morning.

Communities prepare

Newport Beach has declared a local emergency and activated its emergency operations center, reinforcing sand berms and installing thousands of sandbags on Balboa Island. The city expects tides of about 8.3 to 8.5 feet on Monday through Wednesday mornings.

Metrolink said it is suspending commuter train service in southern Orange County and San Diego County for the coming workweek because of the forecast, while Caltrans is placing sand-filled barriers beneath a cracked stretch of Highway 1 near Crystal Cove.

In the Bay Area, the weather service warned of up to 1.9 feet of inundation in low-lying areas near shorelines and tidal waterways, with the highest tide expected just before 1 p.m. Wednesday at the San Francisco gauge. Officials warned residents not to drive around barricades or through water of unknown depth.

Worse may be ahead

Scientists say the threat may grow this winter, with even higher tides expected around Thanksgiving, Christmas and Martin Luther King Jr. Day. The greatest danger would come if those king tides coincide with strong storms.

“It’s likely to get worse before it gets better,” Daniel Swain, a climate scientist with UC Agriculture and Natural Resources, told the Times.