Most snowflakes aren't, the vast majority of snowflakes are of the "irregular" type. And to answer another person's question above "Why are snowflakes 2d", the

Most snowflakes aren't, the vast majority of snowflakes are of the "irregular" type. And to answer another person's question above "Why are snowflakes 2d", the irregular ones aren't, and there's a lot of symmetric ones that aren't 2D either[1]. The ones people like to photograph are the symmetric 2D ones, so there's just a lot of selection bias going on. But, the ones that are symmetric, are that way because all of the branches experienced the same environment on the way down. Most of them are not perfectly symmetric, and differ quite a bit, but photographers tend to select only the most symmetric ones. The website in [1] has an overview of how to get started in snowflake photography if you want to give it a try. I've done it quite a bit myself, but unfortunately I don't get the opportunity very often. [1] http://www.snowcrystals.com/guide/snowtypes4.jpg http://www.snowcrystals.com/guide/snowtypes4.jpg