Key takeaways
- Black ice is clear, thin ice that lets dark pavement show through, so it looks wet, not icy.
- At home it usually comes from meltwater that refreezes: snow piles, roofs, downspouts.
- The riskiest mornings follow sunny afternoons, when snow melted and then froze again overnight.
- Fix the water source, clear slush before dark, and treat known spots in the late afternoon.
On this page
What is black ice?
Black ice is not black. It is a thin, transparent layer of ice that forms without the bubbles and texture that make ordinary ice look white. Because it is clear, you see the dark pavement through it, and it looks like a wet patch. That is what makes it dangerous: nobody slows down for a wet patch.
Where it forms around a home
Black ice needs water and a surface at or below freezing. Around a house, the water almost always comes from somewhere nearby:
- Below downspouts that empty onto the driveway or walk.
- Beside snow piles, which melt on sunny afternoons and run across the pavement.
- At the bottom of a sloped driveway, where meltwater collects.
- At the apron, where water from the driveway meets the road plow's ridge and has nowhere to go.
- On shaded walks and steps, where the sun never finishes the job.
- In low spots in parking lots, where water pools.
If one spot ices every time, it is a water problem, not a salt problem. Our guide to why a driveway ices in the same spot walks through finding the source.
Why the worst mornings follow sunny days
A sunny afternoon at 30°F can still melt snow on dark pavement and on the sunny side of piles. The meltwater spreads out in a thin sheet. Then the sun sets, the sky clears, and the temperature drops fast. By morning, that sheet is a glaze of clear ice. Clear, calm, cold nights after a melt are exactly when black ice forms.
How to prevent it
- Put snow piles where meltwater drains away from the pavement, and never at the top of a slope.
- Extend downspouts so they discharge onto the lawn, not the driveway.
- Clear slush before dark. Slush that is pushed off the pavement cannot refreeze on it.
- Keep the storm drain at the curb open so water leaves instead of pooling at the apron.
- Treat known trouble spots in the late afternoon, before the temperature drops. A small amount of de-icer on dry pavement, applied ahead of the freeze, keeps ice from bonding. This is the idea behind anti-icing.
Dealing with it in the morning
- Traction first. Sand or grit gives grip immediately, at any temperature.
- Melt second. Rock salt slows badly below about 20°F and stalls near 15°F; calcium chloride keeps working far colder.
- Walk like a penguin: short steps, feet flat, weight over your front foot. Ice cleats help on steps and slopes.
For businesses
On commercial sites, black ice after a thaw is one of the most common slip-and-fall conditions. A walk-through of entrances, ramps and low spots before opening, with treatment logged, is standard practice. See snow logs.
Sources
- Minnesota Stormwater Manual: how salt works and deicing chemicals — practical working temperatures
Written by the Macomb Lawn & Snow Solutions team in Macomb Township, Michigan. We plow and salt homes and businesses across all 26 Macomb County communities, November 15 to April 15. Published September 28, 2026. About us · How we research these guides · How our dispatch works