I remember this shareware game for the Atari ST back in the day called Snowball Fight. One of the cool features it had was that the 'ground' level would change as snow fell, players picked up snowballs, and snowballs landed on the ground. I have been thinking about how to accomplish this, but I'm can't think of any way to do it but to have an array to track the height of the ground at certain points across the screen. Does anyone know of a better/cooler way to do it?

There's nothing wrong with an array representing snow depth. It would be easy and fast.

I'm sure that you could come up with something really complex and inefficient if you try hard enough

you could have a 2d array of depth at certain cells and then interpolate the points to create a smoother surface, and during render time, translate some points for snow prints (footprints, snowangels, etc.) during render time.