Even though we haven’t had any in a while, I often get this question: “Last winter, we had what I have always called “corn snow”. When I mentioned it to my co-workers, they asked me what was the difference between hail and corn snow, and I couldn’t come up with an acceptable answer. Is there a difference? Or is it just a winter vs. summer phenomenon?”
Corn snow can mean many things. Skiers use the term to describe snow that has gone through a few freeze-thaw cycles. But I think what you are talking about is a common term for Graupel, or snow pellets. There are some meteorological similarities between graupel and hail. Both are formed in convective storms, meaning there has been a lot of upward and downward movement of air, which either melts (in the case of hail) or partially melts (in the case of graupel) the original snow crystals. The end difference is hail is solid ice throughout, and graupel is still snow that is compressible.