This hail stone found by a farmer near Vivian, SD, could be among the largest ever recorded in the United States, nearly 8 inches in diameter. Photo by Aberdeen National Weather Service office
HAMILTON COUNTY, TN (WRCB) -
We're in primary severe weather season, and one of the things we get with storms is hail. We've heard it described as quarter size or dime size. Then there's hen egg size and teacup size.
The descriptions sound strange, but the National Weather Service (NWS) has a list of these objects it uses for hail size comparison. The way it probably started 100 years ago or more was when a lot more people lived in rural areas and they used familiar objects to compare the size of hail that fell at their farms. For example, we had hail here as big as our hen eggs. This is how it was reported to the NWS which then measured the diameters of these objects and made an official list, later adding modern objects.
Sometimes different size hail falls in same location. The largest size is what should be recorded. So if you get penny and quarter size hail at the same spot, the official size will be recorded as quarter size.
The proper way to measure a hail stone is to estimate the diameter which is the distance across the stone between the two furthest points. This can be estimated using a ruler. Don't use a tape measure wrapped around the stone. This is the circumference. Use this for your own records, but it's not the official size if reported to the NWS.
According to the NWS office in Morristown, TN, the largest hailstone on record in Hamilton County was found in Birchwood in May of 2006. It was the size of a baseball.
The largest in the U.S. was found in South Dakota in 2010 and was almost twice as big as a softball!