What Are Snowflakes?
Snowflakes are made of ice. Each snowflake is made of as many as 200 ice crystals.
Some snow crystals are symmetrical, like the type that you cut from paper. They form a hexagonal shape because that is how water molecules organize themselves as they freeze. Others are small and irregularly shaped. If they spin like tops as they fall to the ground, they may be perfectly symmetrical when they hit the Earth. But if they fall sideways, they will end up lopsided.
Because there are so many ways that molecules can arrange as water freezes, some people say that there are no two snowflakes alike. Probably no two snowflakes have exactly the same arrangement of molecules. But they can look pretty similar.
How Snowflakes Form
Snowflakes form in clouds where the temperature is below freezing (0ºC, or 32ºF). The ice crystals form around tiny bits of dirt or pollen that have been carried by the wind. As the snow crystals grow, they become heavier and fall toward Earth. Different types of snowflakes form in different conditions. Temperature determines if the crystals become a flat plate, a long column, or a prism shape.
On average, 10 inches of snow melt down to about an inch of water; however, not all snow is the same. Some places receive very heavy snow. For instance, only five and a half inches of January snow on Mount Washington, New Hampshire, melt down to an inch of water but over 15 inches of January snow at Crested Butte, Colorado, melt down to an inch of water.