Black ice is one of the most dangerous conditions for drivers when the weather gets cold. The reason is quite simple -- it’s really hard to see.
Black ice is almost perfectly clear with no trapped air pockets. It is only black because of the paved road underneath.
In order to be clear, a couple of conditions have to be met. First, the water has to fall gently. A heavy, splashing rain will create bubbles and swirls in the ice. So heavy fog, misty rain or even condensation from a vehicle’s exhaust can all create black ice
The other big condition is pretty obvious -- it has to be cold enough to freeze. But black ice is often so thin it can form when the air temperature is above freezing.
That is especially true in the early morning hours before the sun can warm roadways. Bridges and underpasses are the biggest culprits. Cold wind can whip around bridges bringing down the surface temperatures and underpasses often don’t get enough sun to warm the roadway.
So what do you do if you hit black ice? It may be counter-intuitive for drivers. If you feel your wheels slipping, take your foot off the gas, resist the urge to slam down your brake pedal and coast until you get traction again. If you start to skid, steer into the skid instead of away from it.