Once in a blue moon: How a rare lunar event sent post-landfall surge into Wakulla County

ST. MARKS — Hurricane Idalia spared Wakulla County from catastrophic storm surge when it zigged to the east Wednesday – but the storm, combined with a rare super blue moon, conjured unusual post-landfall flooding at the coast.

Late Tuesday, as Idalia was heading toward the Apalachee Bay coast, Wakulla County was bracing for storm surge well beyond what was seen during Hurricanes Michael or Hermine. Had the storm made landfall west of Wakulla County, St. Marks, Shell Point and other towns just south of Tallahassee could have seen 8-12 feet of life-threatening surge, said Kelly Godsey of the National Weather Service in Tallahassee.

But Idalia hit Keaton Beach instead around 7:45 a.m., which coincided with low tide. Its off-shore winds actually blew the water away from the Wakulla coast. About an hour after landfall, the water at Shell Point was minus more than 3 feet.

But that quickly changed and by 1 p.m., water levels had risen to 3 to 4 feet above dry land along the Wakulla Coast. Several hours later, it was gone again.

Godsey said two factors caused the post-landfall surge: the mere presence of Idalia in the shallow Apalachee Bay, which tends to rise whenever a storm is in the northern Gulf, and the full super blue moon, which saw it closer to the earth than any other day this year.

A blue moon is unique because it's the fifth full moon of the season, or the "extra" moon. Normally, this occurs only every 2½ years. The second full moon in a month also has been known as a "blue moon" since the 1940s. Typically, this also only occurs once every 2½ years.

"This particular super moon that we just had, it was when the moon was so close to the earth, and that just adds to why the tides were much higher than normal," said Godsey, a hydrologist.

Wakulla County Administrator David Edwards said the storm surge created minor flooding in St. Marks and other places where it's commonly seen during a tropical event. But the timing, he said, was off from past storms.

"That was kind of a post-storm storm surge, which we felt was kind of unusual," he said.

The water surrounded a number of homes in Oyster Bay. In St. Marks, which sits between the Wakulla and St. Marks rivers, the surge sent half a foot of water into the Riverside Cafe and flooded the streets outside. While a mess, it paled in comparison to the surge caused by Hurricane Dennis in 2005 and other storms.

Stan West, owner of the water-side restaurant, and employees had already put the tables and chairs five feet up and stored what they could in a walk-in cooler located several feet above the floor. After cleaning up and disinfecting, West said the cafe will reopen on Friday.

Trajectory of Tragedy: Interactive Hurricane Michael Map

It could have been much worse, he said, with St. Marks wiped out like towns to the west during Michael in 2018.

"We could have been like Mexico Beach ," West said. "I'm super grateful. I feel sorry for the ones who had to get it. Because ultimately, it doesn't matter what you do, somebody's got to get it."

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How to help

• Donate to the  Red Cross by visiting  redcross.org , calling 1-800-RED CROSS (800-733-2767) or texting the word IDALIA to 90999 to make a $10 donation. Sign up to volunteer at  www.redcross.org/VolunteerToday .

• Help feed those in the strike zone through  Second Harvest of the Big Bend at  FightingHunger.org/Idalia .

• Donate to the  United Way of the Big Bend at  uwbb.org/disaster-relief-fund  or text RELIEF2023 to 41444.

With  Tallahassee escaping the brunt  of Hurricane Idalia's wrath, this story is part of a continuing series profiling hard-hit communities. Contact Jeff Burlew at jburlew@tallahassee.com or 850-599-2180.

This article originally appeared on Tallahassee Democrat: Hurricane Idalia, super blue moon send rare surge into Florida county