Erica's Answer:
When looking for freezing fog, don't expect to see tiny ice crystals in the air, though! Fog forms when an airmass cools down to its point of condensation, at which point the water in the air starts condensing into tiny water droplets. In a freezing fog situation, these tiny water droplets are "supercooled", which means that the water is below the freezing point, but still exists in liquid form. When the supercooled water droplet touches a surface, such as your windshield or sidewalk, tiny ice crystals will be visible.- Erica
