Strange weather today: Cold and rainy in the morning, clear and sunny in mid-afternoon, and then a dark and mean-looking line of clouds rolled in just after 5 pm as I was walking across campus. I would have thought a thunderstorm was coming in the summer, but didn't know whether to expect rain or snow this time of year and in this particular (and peculiar) year. We got neither of those:
(Cribbed without shame from Wikipedia.)
Graupel. Not to be confused with Hail or Ice pellets.
Graupel (also called small hail, soft hail, or snow pellets) refers to precipitation that forms when supercooled droplets of water condense on a snowflake, forming a 2–5 mm ball of rime; the snowflake acts as a nucleus of condensation in this process. Graupel is the German word for this meteorological phenomenon.
Under some atmospheric conditions, snow crystals may encounter supercooled cloud droplets. These droplets, which have a diameter of about 10 µm, can exist in the liquid state at temperatures as low as −40 °, far below the normal freezing point. Contact between a snow crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystal. This process of crystal growth is known as accretion. Crystals that exhibit frozen droplets on their surfaces are referred to as rimed. When this process continues so that the shape of the original snow crystal is no longer identifiable, the resulting crystal is referred to as graupel.
Graupel was formerly referred to by meteorologists as soft hail. However, graupel is easily distinguishable from hail in both the shape and strength of the pellet and the circumstances in which it falls. Ice from hail is formed in hard, relatively uniform layers and usually falls only during thunderstorms. Graupel forms fragile, oblong shapes and falls in place of typical snowflakes in wintry mix situations, often in concert with ice pellets. Graupel is also fragile enough that it will typically fall apart when touched.
Graupel is both denser and more granular than ordinary snow, due to its rimed exterior. Macroscopically, graupel resembles small beads of polystyrene.