With the Winter season fast approaching and already showing signs in some parts of the country, it’s important to understand the signs and dangers of one of Mother Nature’s phenomenons: black ice. There really is no big mystery when it comes to black ice. Understanding this Winter roadway danger, will make the new truck driver that more safer if and when black ice is ever encountered.
What is black ice? Black ice is really just “regular” ice without air bubbles. Normally when ice forms on the roadway, tiny air bubbles are trapped inside and once frozen, the ice is visible to drivers due to these air bubbles that we are able to see. Black ice, on the other hand, forms when rain, fog or mist deposits ice along the pavement or roadway in cold weather. The latent heat of the surface will slow down the freezing rate. This slowing down process allows the droplets of water to run together before they can freeze. The air bubbles that are normally within ice are forced out and what is left is a frozen sheet of ice, minus the visible air bubbles, and we end up with a totally clear, transparent layer of ice which takes on the color of the background on which it is lying.
When does black ice form? This form of ice most often forms just around the freezing point of 32 °F, however, due to various atmospheric conditions black ice can form when temperatures are even above freezing. For instance, in extremely cold regions, black ice will form on the frozen ground and roadways although the outside ambient temperatures are above 32 °F. Black ice can form with freezing temperatures even from such things as heat from the tires on the roadway and exhaust fumes from vehicle pipes. Black ice tends to form in the early morning and evening hours. Key factors to remember is that black ice can occur if temperatures are near the freezing mark or even a few degrees above it, and that bridges and tunnels are prime areas.
Black ice awareness: Because black ice is transparent and looks like the surface it is on, it makes it one of the most dangerous road hazards for drivers. While a shiny road surface is a signal as a wet or icy road, black ice simply cannot be seen. However, there is one thing that drivers can make themselves aware of in order to at least be on a better lookout for this dangerous formation:
- Look ahead for pavement that is slightly darker and duller in color than the rest of the roadway or other surface. This is usually the best indicator that black ice is present.
Remember, black ice appears as the color of the material beneath it. When the weather conditions are right for “regular” ice … black ice will most often form as well. Slow down and keep your eyes moving to detect any change of color along the roadway ahead of you. If conditions become too dangerous, stop and park.
Drive safe …
© 2009, Allen Smith. All rights reserved.