How do you melt ice/snow when the temperature is under 5F (-15C)

Question

I live in the mid-atlantic region in USA, where we get the regular change of seasons, and our winters are frequently around 30F (-1C). When it snows, we use rock salt to melt the ice on the sidewalks and roads. However, most rock salt that you would buy at Home Depot/Lowe’s says it works on temperatures as low as 5F (-15C).

So I must beg the question: In areas such as the Great Lakes region or Canada, where winters frequently are below this 5F (-15C) threshold, what do you use to melt the ice if rock salt doesn’t work at these temperatures?

In: Chemistry

Answer 1

You use something like calcium chloride, which works down to -25F, or magnesium chloride, which works down to 0F. There are also some preventative treatments that help prevent ice from forming in the first place, instead of working to melt it after the fact.