The DRY side of Hurricane Irma

The effects of Hurricane Irma were felt across the entire state of Florida. I mean, she WAS huge…

“It’s eye…is wide enough that peak winds could arrive at both sides of the Florida peninsula at the same time…” – Kevin Loria, Business Insider, Sep. 9, 2017

Which is fascinating in and of itself, but for a National Estuarine Research Reserve (NERR), it’s even more interesting. Why, do you ask? Because the state of Florida is home to three(!) NERRs: Guana Tolomato Matanzas in St. Augustine, FL (that’s us!); Rookery Bay in Naples, FL; and Apalachicola in Apalachicola, FL. As such, we have standardized programs for monitoring water quality and weather conditions-which makes for really neat comparison studies.

We have already begun our own investigation into the effects Irma had on our estuary, but our fellow NERRds in Apalachicola have some of their own Irma stories to tell…


The following is a guest post from a few members of our Floridian NERRd family: Rebecca Domangue, PhD and Ethan Bourque.

RD boat pic
Dr. Rebecca Domangue, Research Coordinator, ANERR

Rebecca Domangue is the Research Coordinator at the Apalachicola National Estuarine Research Reserve. At ANERR Rebecca oversees the Reserve’s research and monitoring programs, supervises the research staff, interns, and volunteers, and collaborates with visiting researchers on various projects within ANERR’s boundaries. She had a PhD in biogeochemistry from The University of Alabama on nitrogen cycling, but since her husband is an LSU fan, she can’t say Roll Tide at home. In her free time she likes to fish and knit.


Ethan Bourque is the Water Quality Monitoring

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Ethan Bourque, SWMP Technician, ANERR

Technician for Apalachicola NERR. He has a Bachelor’s degree in Environmental Science and History from Roger Williams University in Rhode Island. Throughout his career, he has monitored water quality for recreational facilities and aquaculture facilities. At Apalachicola NERR, he is responsible for SWMP water quality data collection and QA/QC, equipment maintenance and troubleshooting. In addition to these responsibilities, he also assists with both the marine and terrestrial projects that take place within the Reserve. In his free time, he enjoys activities that involve water in all of its forms, such as skiing and scuba diving.

We wish everyone impacted by Hurricane Irma a rapid recovery and while Irma brought misery to much of Florida, it also presented some unusual data to the NERRds. As Apalachicola NERR spent the days before Irma implementing our hurricane plan, we had to decide whether to leave our SWMP program dataloggers in place at our five monitoring stations. We all agreed the data would be really great to get, especially with the amount of storm surge Apalachicola Bay was predicted to receive. However, we had just spent the last three years upgrading the sondes at these stations to new models and didn’t want to be out $75k in equipment in case Irma didn’t play nice. The recent events of Hurricane Harvey wrecking unretrievable equipment during the storm at the Mission-Aransas NERR was a good lesson in prudence. Ultimately, we decided to pull the new sondes and leave two of the older versions as sacrificial lambs to collect data during the storm at a site near Little St. George Island and a site south of the town of Apalachicola near a commercially important oyster bar. Since these older sondes were being retired, we would not worry too much if they were lost or damaged.

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This is what a datalogger looks like: ANERR’s SWMP Water Quality manager, Ethan Bourque sits with ~$90k worth of water quality datalogger equipment in ANERR’s lab.

(And don’t worry, we made sure to get our missing data excused during Hurricane Irma from the NERR’s Centralized Data Management Office)

What happened during Sunday September 10th and into Monday September 11th was a surprise to us all.

Instead of the storm surge the Florida panhandle was predicted to get, Irma was so powerful and the pressure was so low that it sucked water from its surroundings into the center of the storm. This phenomenon was not unique to Apalachicola Bay and similar effects were noticed in numerous bays along the western coast of Florida.

The unusual ocean activity was not only because of Irma’s wind field but also because of the pressure difference between the eye of the storm and surrounding areas. During high-pressure regimes, the atmosphere above weighs more than beneath a low-pressure center like a tropical system. The dramatic pressure difference between Irma and the rest of the Gulf allowed water to bulge upward since there was less downward force than elsewhere along the Gulf Coast. The low pressure effectively pulled water from the Gulf to the storm’s center and out of the ocean beds around it, leaving shallow coastal areas dry.

Apalachicola Bay went nearly dry. In this picture from ANERR’s coastal training program coordinator, Anita Grove, people are walking on dry bay bottom that is normally under a meter or more of water.

Anita's dry bay no water photo

Remember the sacrificial loggers we left out during the storm?  Their depth sensors recorded the drop in water level.

On the graph created by Ethan Bourque, manager of the water quality SWMP program at ANERR, you can see the significant dip in water level at the two stations. The site near the island, called Pilot’s Cove, recorded low depth of 0.76 meters (or approximately 2.5 feet for non-metric folks) and the site south of Apalachicola, called Dry Bar, recorded a low depth of 0.22 meters (0.7 feet).

Irma depth at Pilot's CoveIrma depth at Dry Bar.png

All that water came rushing back following in the wake of Irma’s eyewall. See how the tidal heights differ in the days before and after the storm? Irma brought more water back in after sucking Apalachicola Bay nearly dry and the tidal amplitudes and ranges were higher following the hurricane.

So perhaps Apalachicola Bay did experience a little storm surge after all!

After the storm passed, ANERR redeployed the new sondes and you can view real time data at: http://cdmo.baruch.sc.edu/ or at http://fldep-stevens.com/


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2 Comments Add yours

  1. Donna Hughes says:

    What did this do to the oyster harvest?

    Like

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