If you can get me the height info then I can just do the snow and glaciers and you apply that to your model so keeping the original erosion. When I move snow about I can either erode as I go or not, it makes no difference to me.

Do you want a greyscale snow depth map or a full HF2 style water height (depth) map as the result ? Also, do you want runny snow or thick viscous style or just take my best guess ? And do you want solar directional heating applied and if so what direction - like the image lighting ?