The Tide: Ga. Coast Braces for Tidal Flooding

Before a drop of rain fell on Friday, some roads and low yards were flooded in marshy areas along the Georgian coast. Along US 80, at mid-morning high tide, the swamp and Savannah River threatened to converge on this single route in and out of Tybee Island.

In Glynn County, the FJ Torras Causeway toward St. Simons was flooded, Glynn County Emergency Management Agency Director Josh Bain said.

This is because it was a higher than normal high tide, called royal tide. Royal tides occur when the moon is full or new and closest to Earth in its elliptical orbit, increasing its gravitational pull on water. The royal autumn tides are usually the highest because the water is near its warmest and widest point, causing sea levels to rise.

The royal tide can be pushed even higher by wind and rain, as you would expect as the weekend goes on.

“We’re looking at an inch to 2 inches of rain,” Bain said Friday. “It’s going to be a bit difficult tomorrow. Stay home and read a book.

The flooding effects of high tides are becoming more common as fossil fuel emissions push average temperatures higher, which in turn raises sea levels. These floods are called tidal floods or sunny day floods.

The National Oceanic and Atmospheric Administration recorded 12 days of tidal flooding at the Fort Pulaski tide gauge last year and forecast five to nine days this year. In 2000, the annual average was two. By 2030, it is expected to climb to 15-25 per year.

Fort Pulaski National Monument delayed its opening on Friday and will delay it again over the weekend to prevent visitors from walking through a flooded entrance area.

On Tybee, the city tried to document flooding for “climate change auditing, funding applications, growth… so many options to provide data when needed or appropriate,” Mayor Shirley sent. Sessions.

But Friday’s flooding there was moderate, Sessions said.

“He didn’t cross the road, nothing significant,” she wrote.

To prevent tidal flooding, US 80 was raised about 8 inches at its lowest points when the road was repaved in 2018.

Cardinal Drive across from Herb Creek on the Isle of Hope on Friday morning November 5 during a rising tide.

With additional royal tides and more rain on the way over the weekend, Tybee officials are still on guard and in contact with the National Weather Service in Charleston.

“The gale blowing NNE at the moment creates variations in tidal patterns and minor changes in wind direction can have significant changes on peak water levels,” Sessions said. “The astronomical prediction is for a tide of 9.05 feet at 9:45 a.m. at the Fort Pulaski gauge. The forecast forecast at this time is 10.7 feet. Depending on weather conditions at high tide, this could change either way. There is usually a 90 minute window to watch for floods from the US 80, and they are usually delayed 30 minutes from the predicted high tide. will need to be closed for a brief period due to flooding and removal of any wreckage/debris from the marsh.

Check out these resources for more information on tidal flooding in Georgia:

NOAA provides several coastal flood resources, including the NOAA Coastal Flood Dashboard, which provides real-time water levels with up to 48-hour forecasts for all tide stations.

The NOAA High Tide Flood Report compares the number of tidal floods each year at each tide gauge. It also provides forecasts of floods expected in the future. Georgia has only one NOAA tide gauge at Pulaski. The nearest gauge to Brunswick is at Fernandina Beach.

The Smart Sea Level Sensor Dashboard maps its sensors and provides real-time data on water levels (and other environmental parameters such as temperature, humidity, and barometric pressure) at 60 sites around the county of Chatham.

The Tide brings regular notes and commentary on news and events by The Current staff.

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