Snow effects are easy to add, you could do it yourself Shamus on a seperate copy of your map if the map creator doesnt enable them.
Check out what I did on my Enceladus map last year. You should copy the "Weather Generator" and "Weather Definitions" portions of code from the "Save" file and also make sure it is enabled in the map's script file with something like this. There are positions which will need to be changed to fit this map, just change the x and z coordinates. The other functions are pretty self explanatory and there is a tutorial floating around the forums somewhere also.
Place this line in your map's script file.
local Weather = import('/lua/weather.lua');