The highest tides of the year are forecast to rise this weekend when the moon’s tug on South Florida waterways is amplified by seasonal conspirators that herald the king tides.
For those who live in flood-prone areas along the Intracoastal, November’s full moon Saturday marks a time to prepare for the brackish water that boils up through storm grates and slips over aging seawalls to flood roads, invade yards, and seep into a handful of homes.
While the spotlight in Palm Beach County is on Delray Beach, where residents on one street sandbag yards and put furniture on blocks to mitigate damage, the tides are an issue from Boca Raton to Jupiter — a nuisance that experts and anecdotes say is growing.
“It’s much worse. Much, much worse,” said Theo Hayes, whose lawn on South Flagler Drive can be half awash in Intracoastal water during fall’s highest tides. “Usually the grass turns really brown and dies. It burned out the sprinkler heads.”
High tides are magnified during full moons as a sun and lunar alignment sandwiches the Earth, creating a greater gravitational pull. Come fall, seasonal elements contribute to the higher tides as summer-warmed water expands and the Gulf Stream slows down, piling more water along Florida’s coast.
Saturday’s moon, which rises at 7:23 p.m. in West Palm Beach, is also near perigee — the closest it comes to Earth in its orbit and another buoy for the tides.
“Then there is the less obvious build up called sea-level rise,” said William Sweet, a NOAA oceanographer who studies tide levels. “The extra water is rising across the globe. It’s sort of ever-present, and more often during this time of year, we are finding these fall high tides spill into communities.”
By 2040, South Florida’s streets could experience significant tidal flooding 10 times per year, according to a 2016 study published by the American Meteorological Society.
The study, titled “In Tide’s Way: Southeast Florida’s September 2015 Sunny-Day Flood,” was released as part of a package of peer-reviewed research papers that examined global extreme weather events and their relation to climate change.
Cities are scrambling to cope with the tidal creep.
In West Palm Beach, a $25 million storm water improvement program includes installing tidal valves that allow water to drain through storm grates, but not flow back up. Delray Beach is in the midst of an extensive study to raise sea walls along Marine Way and Veterans Park. This past year, the city installed valves at drains along Marine Way, arguably the most flood-prone city street, to cope with overflowing drains.
The National Weather Service in Miami cautioned that minor flooding could begin Friday when high tides in Palm Beach County are around 9 a.m. and 9 p.m. Saturday’s highest tides will be about 9:30 a.m. and 9:50 p.m.
But Robert Molleda, the warning coordination meteorologist with the NWS in Miami, said it’s hard to predict how much impact this weekend’s tides will have. In October, strong easterly winds exacerbated tidal inundation, pushing more water toward the coast.
Winds this weekend are expected to be more out of the northeast.
“It won’t be a pure onshore flow,” said NWS meteorologist Chris Fisher.
Still, West Palm Beach resident Lila Young was thinking about the king tide Wednesday with plans to bolster her piecemeal sea wall with donated rocks from nearby new-home construction.
Young, who has lived on the Intracoastal for 30 years, said she’s seen the tides progressively getting higher and flooding her neighborhood more often.
“It’s hard to fight Mother Nature,” Young said. “But I know they’re there and I know they’re coming more and more.”
Approximate high tides
Friday: 9 a.m., 9 p.m.
Saturday: 9:30 a.m., 9:50 p.m.
Sunday: 9:30 a.m., 9:40 p.m.*
* Daylight saving time ends 2 a.m. Sunday .