Winter Weather
Freezing Fog Driving Guide: Visibility, Glaze Ice, Bridges, and Morning Roads
How freezing fog forms, why it can glaze roads and bridges, and what drivers should watch during cold low-visibility mornings.
Quick answer: Freezing fog is fog made of tiny supercooled droplets that can freeze onto roads, bridges, trees, signs, and windshields.
Why it is tricky
Freezing fog can create both low visibility and thin ice at the same time.
Roads may look merely damp until a bridge, ramp, or shaded turn becomes slick.
Where it forms
Cold valleys, low spots, rivers, lakes, and recently wet ground can support fog when winds are light.
If surface temperatures are below freezing, droplets can form a glaze.
Driving response
Use low beams, slow down gradually, and leave extra room.
Treat bridges and overpasses as icy even if the main road seems acceptable.