News Release

Mankato, Minn. – The Minnesota Departments of Transportation is warning drivers of black ice.

“Black ice can be one of the most dangerous conditions on winter roads,” said District Engineer Jim Swanson. “It is almost invisible and can catch drivers off guard,” he added. Black ice is clear and appears black because the dark asphalt surface underneath shows through. It can form on heavily congested highways from auto emissions, but other roads are susceptible including those in shaded areas, near lakes and rivers, in tunnels and on overpasses.

Drivers can increase safety by observing the following tips:

Black ice forms when the air temperature is warmer than pavement, which causes moisture to rapidly freeze and create a thin, transparent layer of ice on the roadway. It can be neutralized with salting and sanding. However, drivers should be aware that salt loses its effectiveness at about 15 degrees and colder.

Too Fast. Too Close. Too Late.
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