Why Does Salt Melt Snow? – ‘The Why’

Why Does Salt Melt Snow?

Welcome to today’s edition of The Why.

Everywhere you look the media is pushing you telling you who to follow, what to watch and when to watch it.   You’re even sometimes told how to do it all.  Truth is, here at American Live Wire we do a bit of that too.  The big difference is we also tell you why.

You ask the questions.  We provide the answers.

“Why Does Salt Melt Snow?” you ask? Today’s question is brought to you by singer-songwriter James Halifko. Currently based in New Jersey snow is something still fresh in his mind. Indeed, according to the lovely Stacy Richards (from this reporter’s favorite Facebook group: You grew up in the Souderton/ Telford/ Harleysville area if you remember…) they had snow flurries about a week ago, believe it or not.

Salt/Image: CollegeGreenMagazine

For those folks this piece is still surprisingly timely and for those more fortunate already experiencing temperatures in the 80s the thought of cold snow might be welcome.  So let’s get to our question: “Why does salt melt snow? “

Your personable penman grew up in Pennsylvania and has hiked up and down snow-capped mountains across the country. Thus this one will be an easy one.  If you live somewhere that has snowfall on a regular basis then you have no doubt seen salt being used to melt the ice and snow on roads and sidewalks.

All well and good but “Why does salt melt snow? “ you ask again? Salt melts snow because it lowers both the freezing and melting point of water.

Scientifically-speaking, it works like this: When water reaches 32 degrees Fahrenheit or 0 degrees Celsius ice forms. When one adds salt, the temperature drops. An addition of 10 percent salt will not freeze until the temperature drops to 20 degrees Fahrenheit or minus 6 degrees Celsius. Add 20 percent and the freezing temperatures drop to 2 and minus 16 degrees respectively.

On a road or sidewalk when the salt dissolves into the water in the ice it lowers the freezing point. It’s actually an observable phenomenon. One can literally watch how ice and snow melt outward away from the salt itself. (Mind you, if the temperature is lower than 15 degrees Fahrenheit the salt cannot get into the ice to begin the process of dissolving it.)

“Why does salt melt snow?” Now you know.

(Hope this edition of the series will help keep you cool over the coming summer months and that you didn’t go snow blind reading it.)

You ask the questions.  We provide the answers.

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