A thick blanket of so-called “radiation fog” descended across large portions of the southeastern U.S. early Friday, triggering urgent warnings from officials and creating hazardous conditions for millions of Americans during the morning commute.
The National Weather Service issued dense fog advisories covering 78 counties across Georgia, South Carolina, and Florida, warning that visibility in some areas dropped to near zero.
Drivers were urged to slow down, turn on headlights, and leave extra distance between vehicles as the fog choked highways and city streets.
Despite the alarming name, radiation fog has nothing to do with nuclear radiation.
Meteorologists say the term refers to fog that forms overnight when the ground rapidly cools under clear skies, trapping moisture near the surface.
While it is not considered directly toxic, officials warned that the dense fog can trap pollutants close to the ground and worsen air quality.
Visibility fell below a quarter mile in many areas, creating dangerous driving conditions.
Major cities affected included Augusta and Macon in Georgia, Columbia and Charleston in South Carolina, and parts of the northern Florida Panhandle. Coastal waters and harbors also saw marine advisories that stretched into the early afternoon.
The dangers of dense fog were underscored by recent deadly crashes linked to low visibility.
In Florida, a multi-vehicle collision earlier this week in Jupiter left one adult hospitalized and killed a 16-year-old child. Officials warned that fog-related accidents often occur suddenly and without warning.
Satellite imagery from the National Oceanic and Atmospheric Administration showed the fog blanketing much of the Southeast early Friday, stretching into Alabama, Mississippi, North Carolina, and Tennessee.
While formal fog advisories were not issued in every state, forecasters flagged the region as high risk due to persistent moisture and stagnant air.
Some residents reported unusual conditions alongside the fog. Social media users in Georgia claimed the fog carried a strange odor and left residue on car windows, prompting speculation and calls for investigation, according to Trending Politics.
Officials have not confirmed any environmental contamination and emphasized that radiation fog is a common weather phenomenon in the region during the winter months.
Meteorologists explained that the fog formed after days of high humidity and light winds, allowing moisture to linger near the surface overnight. As sunlight warms the ground, the fog is expected to burn off gradually. Most land-based advisories were set to expire by mid-morning, though coastal alerts lingered longer.
Health officials cautioned that while the fog itself is not dangerous, trapped pollutants may aggravate respiratory conditions such as asthma, especially among children and the elderly. Residents were advised to limit outdoor activity until conditions improved.
Radiation fog is most common in the Southeast during fall and winter, when longer nights and cooler temperatures create ideal conditions for dense ground-level fog. While familiar to meteorologists, its sudden appearance and dramatic visibility loss continue to pose serious risks for drivers.
Officials stressed that even routine weather events can turn deadly if ignored, urging Americans across the region to take fog warnings seriously as conditions slowly improve.
