Snow is in a continual state of transformation, from new crystals to melted water. Every form of energy input (solar or wind energy, or the mechanical work of a groomer, or skis, on the snow) causes a certain amount of transformation. The response of the snow to the mechanical work that the skis perform on it is perhaps the biggest factor determining the optimal ski/grind/wax set-up. Understanding of energy regimes requires a slightly different way of thinking about conditions, but provides excellent guidelines for making distinctions and decisions.
Snow absorbs little or no energy. Very resistant to change or transformation.
Snow absorbs energy without releasing significant moisture. Crystals transform easily.
Snow releases moisture and develops freezing glaze.
Snow releases free moisture and develops wet glaze.
Snow is saturated – breaks and softens with energy or work input.
Next you should read about transitions.