Q Why are snowflakes individually unique?
— Eric Nost
A Pao Wang, professor in the department of atmospheric and oceanic sciences at the University of Wisconsin-Madison:
Two important factors influence the shape of a snowflake. One is the ambient temperature, and the other is humidity. A snowflake needs to grow under the condition of a super-saturated environment.
The more moisture in the air, the more complicated and intricate the structure of the snowflake will be. So these two factors, the temperature and the super saturation, are the most important factors that influence the shapes.
Folklore says that there aren’t two snowflakes that look exactly alike. That’s just a fancy way of saying that there are thousands of these shapes, and people are always amazed that the shapes can be so complicated and different.
In reality, if you’re looking just with the naked eye, you could see two snowflakes that look almost exactly alike. For example, some snowflakes consist of very simple hexagonal plates with very little design on the surface.
If you were to look into the structure of a snowflake using a microscope, you may see somewhat different structures, but they could be minimal.
With so many shapes that snowflakes can take, the chances of seeing two similar snowflakes in your lifetime are small, although not zero. Most likely you’re going to see many shapes, and it can be exciting to see so many configurations.