Douglas Henderson,  age 10, for his question:

How is snow made?

Snow is not frozen rain. Rain forms from smaller droplets of water in a misty cloud. When it freezes, it becomes icy sleet. Snowflakes are made from much, much smaller particles. It is believed that they form from microscopic particles of vapor in the air.

Billions of these little particles are needed to make one single snowflake  and there is plenty of space between them. Because of their shape, these particles of frozen vapor tend to form six sided crystals. As they form, tiny pockets of air are built into the delicate design. One of these lacy little doilies is called a snow crystal and a sizeable snowflake is a loose bunch of these little crystals. The process of making snowflakes begins when the air is cold enough to turn particles of water vapor into tiny, tiny fragments of ice.