ATLANTA — With a hurricane threatening to bring heavy rain to parts of the Southeast, officials are preparing for potential flash flooding across metro Atlanta, where past storms have shown how quickly rising water can turn dangerous.
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Atlanta officials say crews have been cleaning storm drains ahead of the expected rainfall, but experts warn that the amount of rain and how quickly it falls could overwhelm drainage systems and flood roads and neighborhoods.
“We’re going to have water collecting on our roadways,” Greg Eyerly, commissioner of Atlanta’s Department of Watershed Management, told Channel 2’s Brittany Kleinpeter.
Metro Atlanta has experienced deadly flooding during major rain events. In September 2009, parts of the region received as much as 20 inches of rain in less than 24 hours. Ten people died, including eight who were in flooded vehicles.
More recently, Hurricane Helene brought record rainfall to parts of the region in September 2024, flooding streets and homes and prompting dozens of water rescues.
Dr. Zachary Handlos, director of Atmospheric and Oceanic Sciences at the Georgia Institute of Technology, said the region’s development can make flooding worse, even when rainfall totals are relatively low.
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“Being in a major metro area, we have a lot of paved surfaces, so it really only takes an inch or two inches of rain to have minor flooding events,” Handlos said.
Roads, parking lots and buildings prevent rainwater from soaking naturally into the ground. Instead, water runs across paved surfaces and collects in streets and drainage systems.
Handlos compared the effect to an ice-skating rink, where water has limited places to go and flows from higher elevations to lower ones. That can leave low-lying roads and neighborhoods vulnerable when heavy rain falls faster than the drainage system can handle.
Atlanta’s Department of Watershed Management began cleaning storm drains Wednesday in preparation for the expected rain. However, Eyerly said the drainage system has limits.
“There could be rainfall totals that exceed the design limits this weekend,” he said.
Clearing drains can help water flow more freely, but it cannot eliminate the risk of flooding during intense rainfall. The amount of rain that falls and the speed at which it accumulates can determine whether water drains away or begins rising in streets and surrounding areas.
Handlos said long-term solutions could include creating more green space throughout the city. Vegetated areas give rainwater more opportunities to soak into the ground rather than immediately running across pavement and overwhelming storm drains.
While additional green space would not prevent every flood, it could help reduce the amount of runoff entering drainage systems during heavy rain.
As officials monitor the storm threat, residents across metro Atlanta are being reminded that flash flooding can affect communities well beyond the city limits and that roads that appear passable can quickly become dangerous when water rises.
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