Beachgoers were still dawdling along Fort De Soto Park’s shore when an unexpected large wave rolled in Saturday evening.
Water surged so far and so fast that it plucked patrons’ phones and car keys, pulling them out to the Gulf. Perhaps most notably, the wave flooded shorebird nests, razing the painstakingly nurtured eggs of some of Florida’s threatened birds.
Fort De Soto officials are calling the wave a “sneaker” or “rogue” wave. Luckily, no one was hurt, said Anna Yu, an environmental program manager for the county park.
Yu, who has worked at the park for six years, said she has never heard of a rogue wave striking the beach before. To her knowledge, neither have her colleagues.
“It was kind of a shock to everybody,” Yu said.
According to an unofficial report made by a park ranger, the wave rolled in around 7:40 p.m., affecting most of the west side of the park, or the Gulf of Mexico side of the beach.
The ranger estimated that the wave rolled in about 200 feet further than the highest tide. Only about 30 feet of beach was untouched by the wave. It’s unclear how high it crested.
Yu was not there but said she saw videos and photos of the incident. The water appeared to roll onshore less like a crashing wave, and more like a storm surge, she said.
Yu could only guess what caused the wave. And for now, it remains a mystery.
Rogue waves are greater than twice the size of surrounding waves, according to the National Oceanic and Atmospheric Administration. These kinds of waves are unpredictable, and rare — which makes them difficult to study.
Researchers are still trying to understand how and why these waves form, the administration said.
A water station, hosted by the Florida Department of Environmental Protection, showed an uptick in water levels around Mullet Key at the time of the reported wave.
At 7:24 p.m., the water level was about 0.8 feet, according to a sensor. About 20 minutes later, the water level jumped to about 1.16 feet. The sensor at the Skyway Fishing Pier also recorded a small, jagged jump around the same time.
Meg Palmsten, an oceanographer for the U.S. Geological Survey, said the gauge measures every six minutes, so it’s possible it missed the highest water levels.
Palmsten also floated the idea that it could’ve been a meteotsunami, which is typically caused by atmospheric pressure changes from storms. At the time, radar data showed some offshore showers.
While it’s unclear what led to the rising water, what is clear are the consequences.
Late April is peak shorebird nesting season.
Park rangers and National Audubon Society volunteers worry about human and predator threats to the nesting birds, “but a rogue wave was definitely not on my list,” Yu said.
The park lost “quite a few nests,” she said.
Among them was the nest of a pair of American Oystercatchers. The couple, named AE and Archie, have nested at the park for the past three years.
Their eggs, which were lost, were a week away from hatching.
Oystercatchers are threatened in Florida, as are other shorebirds that lost their nests Saturday.
Volunteers have spent the past month stewarding the oystercatchers and advising people to keep a safe distance from the nest, said Abby McKay, a seabird and shorebird biologist for the Audubon Society.
Bummer is an understatement, she said.
Natural events that disrupt shorebirds can happen throughout the season. But something like this, early on, is odd. Hurricanes, or higher tides, are more common in the later months of nesting season.
“We usually hope that they can get chicks big enough that when we get to that later point in the season, they’ll be able to evade some of those high tides,” McKay said.
McKay expects to see the shorebirds renest.
“We’re trying to align all the stars here, get everything ready so that they feel comfortable again to nest,” McKay said.
Yu also expects to see renesting, but she’s less sure of what AE and Archie may do.
“They might go to Shell Key, they might go to Egmont, who knows,” Yu said.
The park is hopeful, she said, that they’ll come back and try again.
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