Rendered straight from WM. Testing a new snow node. The snow node that's included with world machine is a bit slow and I can't grab the deposition of the snow to use as a mask for coloring or whatever.
Basically I take the flow heightfield from an erosion node, expand it, blur it, crank up the contrast, and then a slope selector mask is subtracted from it. Then I use that result as a blend mask between the eroded terrain and a gently blurred version of it. The blurred version is slightly higher then the unblurred. Simply snow. I still need to optimize this one further as I'd like to get rid of the expander.