I was lurking on here and saw this, and wanted to warn you - you won't get more snow on the ground when it does snow next in your town. The snow actually replaced the grass pattern once it became winter, and when spring comes and the grass comes back it will only appear where you have snow.
The fact that the snow is getting sparse is because of a new feature the programmers added in this version of Animal Crossing. It's called "Animal Tracks". As your character walks around, it wears tracks in the snow/grass. The programmers said that it would take 2 weeks for a path to show up, but it takes much less time than that. Actually, if you watch closely as your character walks you can see the snow disappearing. It does come back, but very slowly. Planting lots of trees and flowers seems to encourage the regrowth but even then it takes a long time. There are many players whose towns look like deserts now.
Several people have started petitions and many people are emailing Nintendo to try to get them to release a patch to fix the issue since it seems impossible to keep grass/snow in a town if several people play in it.
People on one of the AC forums have been trying to figure out the best way to keep or regrow the grass/snow. This is one of the most in-depth threads about it:
http://www.animalcrossingcommunity.com/Topic/3206882/1/The_NEW_AC_CF_Grass_Guide