Black Ice banner

 

Crawford CountyWhile blizzards and ice storms garner a great deal of attention, black ice rarely receives as much fanfare and yet can be just as dangerous to motorists and pedestrians.  Black ice is a very thin, almost transparent layer of ice that forms on roadways and sidewalks.  Because the ice is so thin it is difficult to differentiate it from dry pavement.  Bridges and overpasses can be especially dangerous. Black ice forms easily on bridges and overpasses because air can circulate both above and below the surface of the elevated roadway, causing the pavement temperature to drop more rapidly.

Bowling GreenBlack ice usually forms in one of two ways.  During a sunny day snow melts and the liquid water runs onto road surfaces, and refreezing occurs after sunset when the temperature drops.  Or, rain and/or snow may fall during the day and then temperatures fall below freezing that night.

The temperature of the road is critical.  During a sunny day the air temperature may be below freezing but the road temperature may still climb above freezing, allowing melting to occur, then fall back below freezing at night leading to refreezing. You can investigate road temperatures via the Roadway Information Systems in Kentucky and Indiana.

A pavement surface that appears to be dry but shows varying shades of darkness may have patches of black ice.  In addition to bridges and overpasses, black ice is also common in shady spots.

slippery when wetThe National Weather Service normally issues Special Weather Statements to alert the public to the possibility of black ice.  Motorists should treat black ice the same as any other icy road surface:  slow down and leave plenty of distance between vehicles.  In addition, pedestrians need to step carefully on black ice, especially on stairs and uneven sidewalks.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.