Graupel Versus Hail - Extra Credit Lesson

Early Monday morning across eastern Nebraska, we ran into an area of significant graupel accumulation. It accumulated about an inch deep, made travel treacherous for about 15 miles across I-80, especially during the heavy downfall. In this case the temperature at ground level was about 35. The elongated storm intensified rapidly, then started dropping graupel [just as we arrived underneath it] as it gained more height, then rapidly "rained out" and it was back to a normal rain cell.

Later, another driver was telling the other drivers to look out for the "worst hail storm he'd ever seen". I tried to tell him that wasn't hail but I don't think he believed me. Graupel often occurs in the plains and higher elevation mountain areas, especially in early spring. Many describe graupel as a cross between snow and hail. Graupel will melt much faster than hail.

Hail (big or small) will make a distinctive "crack" when it hits the windshield, graupel on the other hand is more like huge rain drops hitting the windshield and won't hurt anything at speed. Hail has to be kept aloft inside a major storm cell updraft to freeze hard, and larger with time. A hail stone may ride up and fall down 3 or 4 times, in excess of a 10,000 feet, before it's weight overcomes the updraft component of a given storm. Graupel just falls straight down, beginning as snow but picking up freezing H2O as it falls. And sleet, is yet another breed of frozen precipitation.

Graupel: The wintry precipitation you’ve never heard of



And Texas will be under a mostly hail event the next few days, including Monday night. Tuesday and Wednesday.