WHY does salt make snow melt?

Salt solution has a lower freezing point.

There is a thin layer of quasi-liquid water on the surface of ice. It is formed by the fastest molecules that bounce off the ice crystal. At temperatures below zero, these molecules soon “freeze” to the crystal again.

Salt, dissolving in this quasi-liquid layer, slightly reduces the concentration of molecules, slowing their return from the liquid phase to the solid, and the ice melts. Still, of course, in quite severe frost, salting the ice is not enough to melt it.

Categorized in: