Rime & Graupel

Snowflake with Rime (USDA BARC)

Do you know what rime and graupel are? No, they aren't a law firm or something you do when you are refinishing furniture. Rime and graupel are types of snow! Rime occurs when snow crystals encounter supercooled water droplets. The supercooled water turns into tiny ice balls on the surface of the crystal. The ice balls grow by accretion until the original crystal is completely covered in rime. At this point, the rimed crystal is called graupel. Graupel can act like icy ball bearings, allowing layers of snow to slip against each other, which can result in an avalanche if the conditions are right. Otherwise, graupel is the snow that feels like ice pellets when it hits you, basically because that's what graupel is.


Graupel (USDA BARC)