Extreme flooding risk increasing in the next 72 hours; Debby forecast to make a second landfall in South Carolina

“Debby will be recognized as the next billion-dollar weather disaster in theUnited States,” said AccuWeather Chief Meteorologist Jon Porter. “We do not forecast an extreme risk to lives and property from flooding very often. Flooding disasters are possible in multiple communities this week. People need to be prepared for potentially catastrophic flooding. When all is said anddone, in fact, there could be tens of billions of dollars in total damage andeconomic impact from Debby.” 

Debby has slowed to a crawl along the southeast U.S. and is expected to produce up to 2 feet or more of rainfall in parts of Georgia and South Carolina.  The AccuWeather Local StormMax™ is 32 inches near the South Carolina shoreline, where there is the potential for the storm to slow down or stall. Should this occur, flooding could be significant, life-threatening, and historic. 

“Debby has been meandering at a snail’s pace, but it will blast to the northeast like a rocket later this week,” said AccuWeather Chief On-Air Meteorologist Bernie Rayno. 

Porter says the flooding risk extends more than 100 miles inland from thecoastline across much of the Southeast this week.  

“If there is heavy rain inland across the Carolinas, that water will eventually enter rivers and other waterways that flow toward the coast,” explained Porter. “Water flowing from the ocean back toward the coast, coupled with thepersistent onshore flow, can back up the rivers because they won't be able to drain, further amplifying what can already be major flooding concerns along and near the coastal areas.” 

AccuWeather Lead Hurricane Expert Alex DaSilva says Debby will unleash not only heavy rainfall in the Southeast, along with a risk of tornadoes, dangerous storm surge, a rip current risk, and extensive beach erosion. Portions of beaches from Georgia through the Carolinas could be washed away. Across this area, 3-6 feet of storm surge is expected with a small area expected to have 6-10 feet of storm surge.  

“Debby is in an area with very weak steering winds. The storm has essentially hit the brakes and is moving at just a few miles per hour,” explained DaSilva. “We have two areas of high pressure. One over the Plains of the United States, and the Bermuda High to the east. Both are essentially pushing Debby. The Bermuda high is winning right now and keeping Debby onshore over land. We expect the area of high pressure over the Plains will eventually win out and push Debby out over the Atlantic. Debby may strengthen a bit before an upper-level low to the southeast approaches underneath Debby, pushing the storm to the north. Debby will then be picked up by a dip in the jet stream, which will pull the storm up toward the northeast.” 

DaSilva said Debby is expected to make a second landfall along the coast of South Carolina Thursday.  

Wind gusts of 60-80 mph may occur along the Carolina coasts, which could bring down trees and power lines and cause some structural damage. 

AccuWeather expert meteorologists say Debby will continue to create major travel and business disruptions. AccuWeather is forecasting 1,000 flight cancellations Wednesday and Thursday, and 1,200 flight cancellations on Friday.  

Debby is a 3 on the AccuWeather RealImpact™ Scale for Hurricanes in theUnited States due to dangerous storm surge, life-threatening flooding rain, and strong winds. It is still possible that Debby might need to be rated higher than a 3 on the RealImpact™ Scale. This would only occur if the floodingpotential across the Southeast escalates further. 

“There’s a big difference between Debby being a tropical storm on the Saffir-Simpson Hurricane Wind Scale, and a 3 on the AccuWeather RealImpact Scale for Hurricanes. The reason we created this scale is to raise public awareness and relay the urgency of flooding threats and other impacts that are not included in the Saffir-Simpson Hurricane Wind Scale,” explained Porter. “We’ve seen so many cases in the past where people were unprepared or did not clearly understand the risks from a slow-moving, big rain producer like Debby.”