SnowSnow is precipitation that falls as aggregations of ice crystals. If large, these aggregations form snowflakes. An irregular crystal is a particle of snow that consists of a number of very small crystals that have formed erratically, so the resulting particle has an irregular shape. Irregular crystals are sometimes covered with a coating of rime frost. Snow that has an irregular crystalline structure is called amorphous snow. Snow grains, also called granular snow or graupel, are very small particles of white, opaque ice. The grains are flat and less than 0.04 inch (1 mm) in diameter.
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