This is actually my own field (not meteorology, but thermodynamics).

On a phase diagram for water, the vapour-solid equilibrium line is called the "frost line" - the transition from solid to vapour phase is called sublimation.

Unfortunately thermodynamics lacks a standardised term for the opposite transition, from vapour to solid. "Crystallisation" describes a more general phenomenon.

Terms in use include "sublimation", "reverse sublimation" and "deposition".

I usually see (and use) "gases", but I don't know whether "gasses" is acceptable in European English, or whether it is a US variant.


Another useful meteorology term (for pilots, at least) is "virga" - rain or snow that does not reach the ground (it meets a layer of dry air on the way down and evaporates/sublimates). "Virga" is a Latin word for "branch".