A thick blanket of so-called “radiation fog” rolled across the Southeast early Friday, snarling travel and creating dangerous driving conditions for as many as five million people.
The National Weather Service issued dense fog advisories for 78 counties across Georgia, South Carolina and Florida, warning motorists of near-zero visibility during the morning commute.
Despite the ominous name, radiation fog has nothing to do with nuclear radiation and is not considered a direct health threat. Officials have warned, however, that dense, low-level fog can trap pollution near the ground and worsen air quality.
Drivers across the region were hit hardest, with visibility dropping to less than a quarter-mile in many areas.
The dangers were underscored last year when a massive pileup on Interstate 5 in Kern County, Calif., involved nearly 40 vehicles, including 18 tractor-trailers, killing two people and injuring nine others on Jan. 6, 2024.
Meteorologists said fog blanketed central, eastern, and southeastern Georgia, central and southeastern South Carolina, and parts of the northern Florida Panhandle.
“If driving, slow down, use your headlights, and leave plenty of distance ahead of you,” NWS officials wrote in their warning.
Most land-based advisories were set to expire by 10 a.m. ET as sunlight warmed the ground and thinned the fog. Some coastal and marine alerts stretched until 1 p.m., including waters off Georgia and South Carolina, Charleston Harbor, and parts of Florida’s Panhandle bays.
Major cities affected included Augusta and Macon in Georgia, along with Columbia and Charleston in South Carolina.
Florida has been dealing with persistent fog for days, starting along the east coast before drifting northwest.
Local news outlets reported a deadly multi-vehicle crash on Wednesday in Jupiter, Fla., involving several cars. A driver from another vehicle was hospitalized, and a 16-year-old child was killed.
Satellite images from the National Oceanic and Atmospheric Administration showed dense fog covering much of the Southeast early Friday, extending into Alabama, Mississippi, North Carolina and Tennessee.
While no fog advisories were issued for those states, the NWS flagged flood watches in Alabama, Mississippi and Tennessee due to a “moist airmass with a slow-moving surface boundary” pushing through the region.
Dense fog typically forms overnight when moisture lingers in the air after rain or high humidity. Clear skies and light winds allow the ground to cool rapidly after sunset, releasing heat and creating thick fog near the surface.
Before it burns off, pollutants from vehicles and factories can hover for hours, potentially aggravating respiratory conditions such as asthma.
Some Georgia residents claimed on social media that the fog smelled unusual.
“We have had foggy mornings for the last week in NE Georgia. And it’s not normal fog, it smells like burning plastic and leaves a residue on our car windows,” one user wrote Thursday, urging Health Secretary Robert F. Kennedy Jr. to investigate.
Radiation fog is common in the Southeast, especially in fall and winter, when longer nights, cooler temperatures and moisture from seasonal storms help thick fog form close to the ground.
