Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I think I kind of understand this process but I would like someone to explain it more completely.

For those who aren't aware here is the scenario I'm talking about:

As terrain maintenance at my local ski slope we often use salt to firm the snow around jumps on warm slushy days. Throwing down a even layer of salt causes the snow to become firm and icy on its top layer (thus causing jumps to hold up better during heavy use).

My best guess to this phenomena is that the latent heat of vaporization in the melting of some of the snow causes the snow below to become colder. As the snow on top melts it sinks down leaving an icy layer on top.

Am I on the right track? or is something else going on?

share|improve this question
add comment

1 Answer 1

up vote 6 down vote accepted

Salt lowers the melting point of water. When you throw it on snow (in not-too-cold weather), it causes some of the snow to melt, and the snow surrounding it will melt until the concentration of salt is low enough that the melting point of the salt water is above the ambient temperature. This will form a layer of ice. You can achieve roughly the same effect with a hair dryer.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.