Melting snow

Until I came to Iowa, my model for melting snow was the Sierra and Cascade mountains. In the mountains, and when it is undisturbed, snow melts gently and smoothly, keeping a nice surface until it's finally gone. But when snow is disturbed (for example, is shoveled or plowed) it has an uneven surface that can catch the rays of the sun to create melt pockets where melting is accelerated by focusing the sun's rays. Sometimes these pockets will actually melt so much that they leave a light lace-like tracing over them. This can create some very beautiful effects. Look at the images below (he said, going into Professor mode):
The left-hand part of the image shows a photograph of one of these snow pockets. If you look at the right-hand part of the image through a pair of red-green, red-blue, or red-cyan glasses, you can see the same snow pocket in stereo. Click on the image to see a full-sized image; the stereo is much better that way. (This uses a tool to create anaglyphs from stereo pairs that Mike Bailey and I talk about in our textbook on computer graphics shaders. If you want more details, drop me a note...)