Imagine walking out on a cold winter morning and finding the landscape covered with icy snowballs, donuts and jelly rolls.
That’s what happened after the late January blizzard. From Illinois to Pennsylvania, people discovered a playground of snow rollers, rare snow formations normally only found at the South Pole!
Have a donut, complements of the latest blizzard! SOURCE: NOAA
The blizzard brought record-breaking cold – temperatures not seen in a generation. With it, it brought the recipe for snow donuts:
1. Powder snow – Cold air holds very little moisture, so any snow that falls feels as dry and light as frozen talcum powder. It is normally found in Antarctic or high in the Rocky Mountains. Midwestern and Eastern states, used to heavier, wetter snows, prone to turn to slush and ice, found themselves covered with delicate powder snow.
Snow rollers – just add powder snow and high winds. SOURCE: NOAA photo by Jolene Albert
2. Wind packed crusts – Normally, the top layer of snow forms a crust from melting slightly, then refreezing to an icy layer. During the late January blizzard, however, temperatures were too cold to allow any melting. Instead, the high winds packed the powdery snow denser and denser until it formed a thin, light crust.
3. High, rolling winds – As the high winds continued, they caught occasional broken edges of the snow crust. Swooping under, they lifted the layer. It began to roll. Soon it formed a donut or, if large enough, a jellyroll. If the winds continued to roll it, it would pack into a snowball, or a densely layered log.
High winds catch the frozen crusts of snow and roll them like snowballs. SOURCE: NOAA
Although the late January blizzard was technically not a “Polar Vortex” storm, it brought rare snow formations normally only seen in Antarctica. What’s next this winter? Penguins?