These aren't your everyday snowflake photos! Don Komarechka photographs snowflakes, which sometimes reflect beautiful colors inside. How does that happen? It has to do with the lighting, the angle, and the shape of the snowflake itself.
Some light will reflect off the surface of the snowflake, but some will also enter the ice (slowing down due to the density of ice compared to air) and reflect off the inner ice/air boundary back towards the camera. If the ice is thin enough, the distance between the two rays of light is close enough to force them to interfere with each-other now that they are out of sync. Some wavelengths get amplified and others get reduced, resulting in a distinctive color emerging based on the thickness of the ice.
The colors are pretty rare, so you can imagine how many snowflakes Komarechka has shot to get the dozen or so in this article, plus those for his book Sky Crystals. At PetaPixel, he explains the conditions necessary for colored snowflakes, the science behind them, and his photographic technique that captures them. Oh yeah, and there are pictures. -via Boing Boing