I've been working with the details of crop growth simulation in Ancient Savo. As plants grow now they actually consume soil fertility. Weather and moisture also affect growth. This made me re-structure some of the underlying data structures so that snow depth is now stored for each tile. The screenshot is looking westwards, South is to the left. The sunny southern slopes get more sunlight which makes the snow thaw faster. But the northern slopes of hills appear still tinted white because of the snow there.