“Black ice” is a genuine driving hazard. How does it form?
—Jason Stark, Midlothian
Dear Jason, Black ice was originally used to describe a thin layer of new ice on a pond. It appeared dark in color due to its transparency. In the 1980s usage of the term broadened to include the road hazard condition and the term is widely used today. Black ice forms as a thin layer of ice when water accumulates on sub-freezing road surfaces. Because of its transparency, it is invisible and takes on the color of underlying pavement. Unsuspecting motorists driving on dry roads fail to realize they are on an icy surface and go into an uncontrolled spin. This condition often develops at night as pavement temps drop and traffic volume is less.