Black ice dilemma
Almost every driver has experienced it at one time or another.
And it's called black ice.
The name for it is a misnomer. The ice that is named after the dark of night, is actually clear, not black. And it is so clear that it appears to not even exist.
It's invisible effects can put Windex to shame. It is as if someone has cleaned it, shined it and then put it in place, just to trip someone up. And often it does.
Black ice is the result of snow melt, or icy rain that comes out of the sky in one form and then freezes. It is so transparent that it can't be seen on the road through a vehicle windshield. In fact even when standing on the road without being in a car, it can still be invisible.
It's danger is immeasurable. It's like having an invisible grease spill on a tile kitchen floor. It is very slippery. Everything from the smallest compact car to a 150,000 pound coal truck can become its victim. Because black ice contains relatively little entrapped air in the form of bubbles or other visible materials, it is highly transparent. It also ties in with the wet roads around it, thus disguising itself even more.
Road crews can de-ice it with salt which is effective down into the single digit temperatures. Other compounds such as magnesium chloride or calcium chloride can also be used, which lowers the temperature at which the ice will melt.
At very low temperatures (below 0 F), black ice can form on roads when the moisture from vehicle exhaust systems condense on the road surfaces, particularly when there is standing traffic in an area.
Black ice may appear even when air temperature is several degrees above the freezing point of water at times. This happens if the air warms suddenly after a prolonged cold spell yet the road continues to hold the temperature it was before the warm air came in.
While black ice can occur during a storm or after one, prolonged periods of cold with bright sun bring out some of the most dangerous conditions when it comes to driving and black ice. These are conditions that have existed in the eastern Utah area for about the last two weeks.
The reason for the danger is simple and it is all in a driver's consciousness. Drivers surmise that a road looks dry, there has been no moisture for many days, vehicles have been traveling lanes for many days without apparent mishaps and the sun is bright and shining each day. Mostly the road looks dry to the eyes of the driver. It can be deceiving.
What is the answer? Caution, particularly in places where snow exists above a roadway slant where it can melt, run onto the road during the day and freeze at night. Ice can also form on bridges, because of their air flows above and below their structures. Because of this they can have ice on them when everything else on the road is melted. Some of the biggest pileups recorded on American roads have taken place on icy bridges.
Black ice, as invisible as it is, is a reality; one thing that drivers must think about and contend with during the winter months.