One of my traditions upon the first snowfall is to make a snowball slushie with my favorite (non-adult) beverage. When you want to preserve the detail of the snow crystals, get in close and don't hit it with the flash straight on or shoot in direct sunlight. Both options will blow out all of the texture. Either use a bounce flash or natural light in the shade or on an overcast day. Use a darker object in the scene to show off the texture and contrast.