People love snow. They love to ski and sled on it, snowshoe through it, and watch it fall from the sky. They love the way it blankets a landscape, making it look tranquil and beautiful. Few people, however, know how snow works. What makes it possible for us to slip and slide over, whether that's falling on sidewalks or skiing down a mountain? What makes it cling to branches and street signs? What qualities of snow lead to avalanches? In...