A benchmark marathon for Palm Beach County may face a significant detour triggered by sea level rise and king tides — events scientists say will increasingly affect activities of coastal communities.
Sunday’s Fitteam Palm Beaches Marathon coincides with higher than normal seasonal tides that typically cause coastal flooding in the most vulnerable areas of southeast Florida, including portions of the route runners will take along the Intracoastal waterway in the Town of Palm Beach.
That could force organizers to switch to a backup route, a move not expected to be made until Saturday morning, just a day before the marathon.
It would be a crude retreat of sorts, considering this is the first time in the marathon’s history that the route will be on Palm Beach, in an area only about a mile and a half north of Donald Trump’s Mar-a-Lago Club.
The town has warned event organizers that, if the marathon comes into Palm Beach and flooding becomes a problem, the runners will have to turn back, Town Manager Tom Bradford said.
Meteorologists are not expecting this weekend’s tides to rise as high as those in October and November, but they are forecast to surpass the average swell.
Chris Fisher, a meteorologist with the National Weather Service in Miami, said the highest tide for Palm Beach is expected Sunday at about 7 a.m.
The race starts at 5:55 a.m.
Runners will go from West Palm Beach, over the Flagler Memorial Bridge and proceed south on the Lake Trail, along the east bank of the lagoon. Then they head to the Royal Park Bridge, and back into West Palm Beach.
But king tides are expected to result in nearly 4 feet of flooding along the low-lying section of the Lake Trail, Bradford said. The question is whether the flooding will occur between 6:15 a.m. and 7:15 a.m. — the one-hour window when the town is allowing the marathon into Palm Beach.
The only other route between the bridges is Cocoanut Row, but that would force the town to close all or a portion of that road to traffic, which Bradford said it will not do.
“We have made it clear that alternative routes will not be allowed,” Bradford said, referring to the permit granted for the race. “We will not let them to traverse over onto Cocoanut Row [to reach the Royal Park Bridge] if we find the path is flooded. Their only recourse would be to turn around.”
Palm Beach Mayor Gail Coniglio said Thursday that, while the town is concerned for the safety of the marathon participants, the town’s residents are always her priority.
“My first obligation is to the privacy and security of our residents,” she said.
Marathon spokesman Gary Ferman said they are watching the situation closely, and are prepared, if necessary, to alter the marathon route.
“We have been aware of the king tide situation, are monitoring it, and a decision will be made Saturday by noon,” Ferman said. “If changes are necessary we have a backup certified course.”
There’s also the potential flooding on the West Palm Beach side, along the Intracoastal.
But Kathleen Walter, director of communications for the City of West Palm Beach, said November’s king tides weren’t high enough to cause significant flooding on Flagler Drive and city officials don’t expect a problem this weekend.
Fisher, with the National Weather Service, said the flooding won’t be as bad as what happened earlier this year.
“We’ve been fairly dry, and the winds will be gusty but not overly strong,” he said.
Robust easterly winds push more water into the Intracoastal and pile it up along the Atlantic beaches, which can exacerbate king tides. The higher tides of fall are caused by summer-warmed waters in the Atlantic expanding, an annual slowing of the Gulf Stream, and correspond with the extra gravitational pull of full and new moons.
December’s full moon reaches its apex Sunday. It is the closest full moon to Earth this year, which will act as another buoy to higher tides.
Florida Climatologist David Zierden said sea levels have been rising fairly steadily for the past 100 years and “will worsen or increase the frequency of nuisance flooding.”
“But not dramatically so in the next few years,” Zierden said.
By 2040, South Florida’s streets could experience significant tidal flooding 10 times a year, according to a 2016 study published by the American Meteorological Society.
And a January report from NOAA shows that Trump’s Mar-a-Lago Club would be partially submerged if sea level rose 3 feet by the end of the century.
“The underlying trend is clear and it’s growing in leaps and bounds,” said William Sweet, a NOAA oceanographer who studies tide levels. “It’s a building story that doesn’t get that much attention, but this is a disruptive phenomenon.”