I was in Sampson County today for the Hail as the cells came through. The hail was golf ball to baseball-size. The one piece of hail that got my windshield was about the size of two softballs, and looked like a bunch of hailstones and slush stuck together. Is it typical for hailstones to stick or clump together and form such a large mass? Having never been in a severe hailstorm, I was amazed to see something that size fall out of the sky.. Pretty impressive. Unfortunately my car didn't fair too well, but quite a sight to see.
Posted October 14, 2008
MIKE MOSS SAYS: Tim, Sorry to hear about your car, but it sounds like you wintnessed quite the hail event, as baseball sized hail and larger is a rarity in our area. Your observation about the largest hail being composed of smaller components is a common feature of especially large hailstones. When hail is formed by the merging and agglomeration of multiple smaller stones, it is called an "aggregate," and this is usually the form of the record-setting stones. Luckily, this means that these huge stones are less dense than they would be if they were formed with a lot of the smooth, concentric "clear ice" layers sometimes seen in smaller hail stones. Even so, they are representative of violent processes within thunderstorm cells intense enough to produce them, since updraft velocities required to suspend the hailstones while they form are on the order of 50 mph and up for golf ball sized hail, 80 mph or better for baseball sized stones, and 100-120 mph for softball to grapefruit sized hail.