A thick blanket of what meteorologists call “radiation fog” rolled across much of the Southeast early Friday, snarling travel and turning the morning commute into a white-knuckle experience for millions of people. The fog stretched across large portions of Georgia, South Carolina, and Florida, prompting dense fog advisories from the National Weather Service for 78 counties and impacting as many as five million residents.
Despite the ominous name, radiation fog has nothing to do with nuclear radiation. It is a naturally occurring weather phenomenon that forms when moist air near the ground cools rapidly overnight, trapping fog close to the surface. Still, the conditions it creates are no joke. Visibility dropped to less than a quarter-mile in many areas, making driving especially dangerous during the morning rush.
Meteorologists said the fog was thickest across central, eastern, and southeastern Georgia, central and southeastern South Carolina, and parts of Florida’s northern Panhandle. Cities like Augusta and Macon in Georgia and Columbia and Charleston in South Carolina were among the hardest hit. In Florida, fog has been a recurring issue for days, first along the east coast and then drifting inland.
The National Oceanic and Atmospheric Administration confirmed the scale of the event through satellite imagery, which showed dense fog blanketing much of the Southeast early Friday morning. The fog even extended into Alabama, Mississippi, North Carolina, and Tennessee, though those states were not placed under formal fog advisories.
While radiation fog itself is not considered a direct health threat, officials warn it can trap pollutants near the ground. Exhaust from vehicles and emissions from factories can linger in the stagnant air for hours before sunlight burns the fog off. For people with asthma or other respiratory conditions, that combination can be irritating at best.
The danger is primarily on the roads. The risks were underscored by a deadly multi-vehicle crash in Jupiter, Florida earlier this week that killed a 16-year-old child and hospitalized another driver. Officials continue urging motorists to slow down, use headlights, and leave extra distance between vehicles when fog is present.
Most land-based fog advisories were expected to expire by mid-morning as temperatures rose, though some coastal and marine advisories were set to linger into early afternoon. Meanwhile, flood watches were issued in parts of Alabama, Mississippi, and Tennessee due to a slow-moving, moisture-heavy weather system.
Adding a strange twist, some Georgia residents took to social media claiming the fog smelled unusual and left residue on car windows. One user even urged Health and Human Services Secretary Robert F. Kennedy Jr. to investigate. There is no evidence supporting anything beyond ordinary fog mixed with pollution, but in an era where trust in institutions is thin, even the weather gets side-eye.
Radiation fog is common in the Southeast during fall and winter. Long nights, high humidity, and calm winds create perfect conditions for it to form. It is not mysterious, not sinister, and not new. But as Friday morning showed, it is still dangerous enough to demand respect, patience, and a lighter foot on the gas pedal.