Black ice, freezing fog — terms I hope we don’t see in many forecasts this winter

The mention of “freezing fog” in recent local forecasts has more than a few folks scratching their heads, because they’ve never heard of fog freezing before.

But it happens – particularly on mountaintops exposed to low clouds. Freezing fog occurs when liquid fog droplets freeze to surfaces, forming what is called “white rime ice.”

Not rhyme ice. Rime ice…which according to the Web site MiMi.hu is “an opaque coating of tiny, white, granular ice particles” that form when water strikes a surface well below 32F and rapidly freezes.

Black ice, by contrast, is a thin – almost invisible – layer of ice formed when rain falls on a surface that is below freezing. It is especially dangerous, because it is difficult to detect…until you’ve lost your footing or your car is gliding somewhere out of control.