Every Snowflake Has Six Sides

Snowflakes come in endless patterns, but they share one rule. NOAA explains that a snowflake begins as an ice crystal. As it falls, water vapor freezes onto that first crystal, building new crystals that become the six arms of the snowflake. The symmetry comes from inside. The crystals reflect the internal order of the water molecules, which arrange themselves in predetermined spaces to form a six-sided snowflake. Temperature, and to a lesser extent humidity, decides the basic shape. If conditions change as the flake falls, the arms may branch off in new directions, but NOAA states that the six-sided shape is always maintained. Because each arm experiences the same conditions, the arms look identical. Individual flakes take different paths through the sky, so they all tend to look unique.