If you live in a place where snow falls a lot, odds are you’ve heard more than one name for the stuff that’s not snow, sleet or hail. Graupel are soft, small pellets formed when supercooled water droplets at temperatures below 32º F freeze onto a snow crystal. Graupel shouldn’t be confused with sleet, which is sturdier and more frozen. Graupel is encapsulated by ice, and although that might sound like hail, it’s not. Hail is formed from raindrops that are lifted upward into freezing air by wind drafts. Frozen hailstones can start as small as single raindrops that fall, but as the process continues they grow in size and dimension as more and more rain freezes to the hailstone. Hail usually occurs during severe weather, while graupel doesn’t have to be. All it needs is cold, winter-like temperatures. Graupel has the appearance of riced cauliflower, and this gives us a clue as to the origin of its name. The word graupel is derived from “graupe,” which is the word for pearl barley. Graupel can encapsulate many objects, including trees and branches, resulting in a winter wonderland of glittery surfaces.
