Ice on Asphalt Question

[seattleguy]

Here is a brain stumper and I figure someone on here might have an answer. I have ice all over my asphalt at car wash. It is 40 degrees at 7pm. It froze the night before down to 28 degrees, but warmed up into high 40's today and was sunny. How can I have ice when it is no where close to freezing?

 

[Randy]

It was 21 last night 40 miles South of Seattle. Where ever the sun doesn’t shine I have ice all day on the asphalt, the ground gets cold and stays cold. I go to Lowes and buy Water Softener salt in the blue bag and spread it around the lot. I only use 2 or 3 bags a year. It’s 27 down at the wash now.

 

[seattleguy]

39 here. You must be right. It was in direct sun most of the day. weird.

 

[robert roman]

One of the properties of asphalt is it retains energy (heat and cold).

On a hot, sunny summer day, the temperature near the surface of a well travel asphalt road is usually several degrees warmer than the ambient air temperature.

After the sun sets, the air cools down but the asphalt will continue to emit the stored-up energy, warmer air, for hours.

During winter, asphalt absorbs the cold like a sponge. If ice forms over top and is thick enough, it acts like an insulator and will prevent sun’s energy from reaching asphalt.

It’s worse with faded asphalt because dark colors absorb solar radiation better than light colors.

This is why some operators choose to install underground heat systems.

 

[Rudy]

Are you on level ground? Is the ground surrounding you level?

My wash is located in hilly terrain. We have a tie wall around one side (14ft. high), and a smaller one in the back.

I've noticed that cold air flows down the hill, and across my wash. In the winter, I have the same phenomena. The hill stays cold which makes this even worse.....