The National Weather Service issued a Flash Flood Warning for Alpharetta and Milton on Friday, July 24, after Doppler radar showed thunderstorms dumping 1 to 2.5 inches of rain across northeastern Fulton County by mid-morning.
The warning, issued by the NWS office in Peachtree City at 9:53 a.m., remains in effect until 4 p.m. Friday. Forecasters said flash flooding was "ongoing or expected to begin shortly" at the time of the alert, with rainfall rates of 1 to 2 inches per hour and an additional 1 to 3 inches possible on top of what had already fallen.
A separate Flood Watch also remains in effect through Friday evening for the broader north Georgia region, including Forsyth, Cherokee, Dawson, and Hall counties.
What's driving the rain
The NWS attributed the flooding threat to repeated rounds of rainfall along a stalled frontal boundary and what forecasters called an "anomalously moist environment" over Georgia. Warm, tropical moisture from the remnants of Tropical Storm Bertha is pooling along the stalled front, fueling widespread showers and thunderstorms across the Southeast, according to the FOX Forecast Center.
The NWS warned that widespread totals of 1 to 3 inches are likely through Friday night, with locally higher amounts of 5 inches or more. Urban areas and spots with poor drainage face the greatest risk.
Where flooding is expected
The NWS specifically named Alpharetta and Milton among nearly 20 communities expected to experience flash flooding. Others on the list include Roswell, Johns Creek, Peachtree Corners, Cumming, Gainesville, Duluth, Sugar Hill, and Suwanee.
Forecasters warned of flooding on small creeks and streams, highways, streets, underpasses, and other low-lying areas. In hilly terrain, the NWS noted hundreds of low water crossings that become dangerous in heavy rain.
What residents should do
The NWS urged drivers to avoid flooded roads entirely, invoking its "Turn Around, Don't Drown" safety campaign. Most flood deaths occur in vehicles, the agency said, and residents should find alternate routes rather than attempt to cross standing water.
The NWS advised residents in flood-prone areas to monitor updated forecasts and be prepared to act if flooding develops.
Neither the Alpharetta Police Department nor the Milton Police Department had confirmed specific road closures or flood-related incidents as of Friday morning.
Residents can monitor real-time NWS alerts for the north Georgia forecast area at weather.gov/ffc and find flood safety guidance at weather.gov/safety/flood.
