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The Secret behind Black Ice

By: Fion Lim

Have you ever heard of Black Ice? If you’re living near the equator, you probably haven’t before but if you have, stay anyway! I’ll tell you about all the things I know about it!

First off, what is Black Ice?

Black Ice is a layer of transparent ice on the road, it is most frequent during the winter. It causes above 550,000 crashes annually in the United States. (It’s a huge number for something that are only around for 3-4 months a year!)

How are they formed?

They are formed on relatively dry roads (one reason why they are nearly invisible for drivers). It happens when textures present in pavements contain water or moisture, the roads will look dry and safe to drive through until the water or moisture freezes and expands.

It can also be formed after a light drizzle with below freezing temperatures.

Why are they so dangerous?

For a normal road, it is dangerous because drivers cannot see Black Ice, they are way harder to detect compared to snow, ice pallets (raindrops that have frozen before hitting the ground) or sleet (mixture of rain and snow).

But it is especially dangerous for bridges and overpasses. It is because air can circulate the road from above and below, giving a perfect environment for Black Ice to form easily. Bridges are where Black Ice will spawn first.

Example of Black Ice on the road

Black Ice does not only form on roads, they can also be formed on water. It happens when the temperature is below freezing and the wind is calm, then a thin layer of Black Ice will form on top of a lake.

Black Ice on lake

Beware when stepping on frozen lakes! They may look frozen but it could just be Black Ice and you’ll fall through! (Could be fatal!)


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