Tropical Storm Debby could bring 'historic' flooding to SC (2024)

The National Weather Service's Charleston office is raising a series of alarms about Tropical Storm Debby's potential to bring "historic" rainfall to coastal South Carolina.

Debby is anticipated to make landfall in Florida early Aug. 5 and push through Georgia before slowing and potentially stalling out over coastal South Carolina near the middle of this week. The NWS Aug. 4 forecast indicated that Debby could drop 10-20 inches of rain across the region, with localized amounts as high as 30 inches.

"We're looking at rainfall values… two to four times the entire month's average rainfall in just a few days," Ron Morales, a meteorologist with NWS' Charleston office, said in an Aug. 4 briefing.

In anticipation of the storm, Gov. Henry McMaster has declared a state of emergency.

"With a potentially significant rainfall event forecast for the next few days, it is critical that residents in potentially affected areas start making preparations and plans today — in case it is necessary to take quick action," he said in a press release.

Residents can find resources to help weather the storm online athurricane.sc.

Morales said coastal South Carolina will likely start feeling Debby's effects on Aug. 5, and the storm will persist for several days.

"There's indications in the models that we could be dealing with this system in some way, shape or form — especially with heavy rainfall and flooding — through Friday (Aug. 9) and maybe even beyond," Morales said. "We're hoping that doesn't happen, but the models continue to show that trend."

The forecast could change in the coming days. But the current predictions by NWS put Debby in the same league as an October 2015 storm system that caused what is colloquially called the "thousand-year flood."

The 2015 system dropped about15-20 inches of rain,with localized amounts up to 25 inches, according to the Weather Service. The system washed out entire communities, ruptured dams and killed19 people.Then-President Barack Obama declared it a disaster. It took state officials six years to fully repair all of the homes damaged in the floods.

"(Debby) is oriented differently, covering a lot of our coastal city areas, which is where a lot of people live," Morales said. "Therefore, more impacts."

Morales said, looking at Debby another way, the storm's rainfall combined with the duration of the event have around a 0.1 to 0.2 percent chance of occurring in any given year.

"This is a very historical type of rainfall that we're forecasting," he said.

NWS forecasts that Debby could also bring powerful winds and up to 4 feet of storm surge to near-coastal communities, like Charleston, flooding streets and causing minor to moderate beach erosion across the coast. NWS issued a storm surge warning for the entire southeast South Carolina and Georgia coast the evening of Aug. 4. The warning indicates that there is a "danger of life-threatening inundation" from sea water pushing in from the coast through the morning of Aug. 6.

A flood watch has also been issued for areas further inland in Berkeley, Charleston, Dorchester, Colleton, Beaufort and other coastal counties.

The city of Charleston has activated its flood mitigation plan and is planning for widespread road closures due to flooding. Updates on streets closures can be found on the city's website atgis.charleston-sc.gov/road-closures-regional/.

"In terms of the amount of rainfall that's going to come down on our community, this is unprecedented," Charleston Mayor William Cogswell said in an Aug. 4 press conference."Our system is not designed to handle this kind of volume in this short a period. The risk of intense flooding cannot be overstated."

Charleston braces for storm

Rain trickled down in Hampton Park as a steady stream of cars with hazard lights lined up along a stretch of the park's mile-long circle. It was business as usual for some as joggers sweating in the sticky, yet cool air passed families moving quickly to fill white bags with sand.

"I haven't seen a rain projection quite like that," Josh Reda, a 26-year-old Charleston resident, said at Hampton Park.

How worried people are about Debby depends on where they live. Reda lives about half a block from Colonial Lake. He moved to Charleston about eight years ago. His street floods with 3 inches of rain, he said.

"This might be pretty disastrous," he said of the possible repeat of 2015's flood.

Sydney Van Bulck, a 37-year-old West Ashley resident, remembers the 2015 flood and how the waters almost reached her door at Middleton Cove apartments.

"I'm more worried about my car, personally, more than anything else," Van Bulck said.

By midday on the peninsula, grocery stores and gas stations had few lines. Shelves of bottled water and canned goods remained well stocked.

Cogswell called an emergency City Council meeting at 5 p.m. Aug. 4 to pass emergency ordinances. Cogswell declared a state of emergency for the city via executive order, following a similar move from McMaster earlier in the day.

The emergency ordinances, which are common during severe storms or emergencies, allow the mayor to set a curfew, close certain roads and prohibit traffic on the Charleston peninsula.

“We’re looking at obviously unprecedented amounts of rainfall,” Cogswell told council members during a virtual meeting. “We don’t want people trying to drive.”

People who live in low-lying, flood-prone areas should consider relocating, Chief Fire Marshal Michael Julazadeh said.

“If your vehicle or street parking in an area that you know floods, it’s going to flood during this event, you need to move it to a parking lot,” he said. “We’re trying to prevent the rescues.

“Once the storm begins, we need to discourage people from moving about the city because we’re just going to end up with more rescues,” Julazadeh added.

Street sweepers and pump trucks began clearing debris and emptying flood-prone areas of already accumulated water on Aug. 4. City employees are staging barricades ahead of street closures, and Cogswell and other city leaders strongly advised residents to follow emergency orders and alerts from city leadership.

"We are ready for the rescues, we are trained for the rescues, we are prepared for the rescues," Charleston Fire Chief Dan Curia said at the Aug. 4 press conference."The best scenario for us is for there to be no rescues."

Trash pickup is expected to occur Aug. 5, per usual, but the city will start shutting down by midday.

Charleston County will open a general population and pet shelter at 3841 Leeds Ave. at 8 a.m. Aug. 5, and it will remain open throughout the storm.

The city of Charleston is opening the following parking garages for free to the public until Aug. 8 at 8 a.m.:

• Aquarium parking garage (24 Calhoun St.)
• Visitor Center parking garage (63 Mary St.)
• 99 WestEdge parking garage (99 West Edge St.)
• Charleston Tech Center parking garage (997 Morrison Drive)
• East Bay/Prioleau parking garage (25 Prioleau St.)
• The Queen Street parking garage (93 Queen St., opens for free parking on Aug. 5 at 5 p.m.)

The County parking garages at 90 Cumberland St. and 85 Queen St. downtown will also be open for free parking during the storm.

It isn't just Charleston preparing for the storm. Communities up and down the state's coast began preparing for Debby's arrival.

Wet week ahead

Closer to the Georgia border, Lane Sprinkle, 15, prepared for the first major weather event of his life. Sprinkle moved to Bluffton from Greenville five years ago where storms like the incoming Debby are a rare sight.

“Our house is downhill. All the water runs straight to the house. It’s not good drainage,” he said, taking a break from shoveling sand into green plastic bags provided by Beaufort County.

After he finishes shoveling sand, Sprinkle will pick up water and ice, and he is contemplating purchasing a generator.

The storm wasn’t all bad news for Sprinkle, smiling at the thought that his first day of school, scheduled for Aug. 7, may be postponed.

Up the coast, heavy rains and flash flooding remain the major concerns for officials in Horry and Georgetown counties. They have asked residents to clear gutters and storm drains ahead of the downpours. Expected rainfall ranges from 12-20 inches.

“We’re still evaluating the forecast to determine those impact areas,” Georgetown County Emergency Services Director Brandon Ellis said. “That will drive decisions such as where shelters will be open and things of that nature in the coming days, if they’re necessary.”

Georgetown County’s emergency operation center will be staffed starting Aug. 5 with increased staffing on Aug. 6. The increased staffing will last for the duration of the storm.

“We’ll be releasing more information as the days go along and as the situation intensifies, but for now we just want everyone to prepare and stay up to date on the most recent forecasts and most recent guidance and information put out by official sources,” Ellis said.

In Horry County, low-lying areas in Socastee and Conway have been plagued by flooding during other wet storms in 2015, 2016 and 2018. Although flash flooding is the immediate concern, officials said rainfall totals will determine the risk of rivers overflowing their banks.

Some residents have been inquiring about where they can find sand for filling sandbags. Horry County officials do not have a sandbag site, but Conway opened one Aug. 4 at 1710 Freeman Drive.

Slowing storms increasingly common

The National Oceanic and Atmospheric Administration reports that it's becoming increasingly common for tropical storms like Debby to slow after they make landfall, spurring disastrous flooding as they stall out.

The same thing happened with the tropical system that caused 2015's thousand-year flood and with 2018's Hurricane Florence, which held near North Carolina's coast for 58 hours. The pause earned Florence the designation of "wettest tropical cyclone on record for the Carolinas," according to the National Aeronautics and Space Administration.

There's evidence that the slowing speed of hurricanes is linked to human-caused climate change, although NOAA'sGeophysical Fluid Dynamics Labcontends more research needs to be done before directly linking the two factors.

But climate change-caused warming oceans can create powerful and more erratic hurricanes, which feed on hot water to grow. June 2024 was the 15th month in a row with record-hot global ocean temperatures, according to NOAA. Due partially to that heat, NOAA issued its most aggressive hurricane forecast ever for the 2024 Atlantic season, which runs through November.

Ali Rockett, Mitchell Black and Dylan Ortuno contributed reporting.