Have you ever wondered how hail is formed? Or just how big it can get? The largest hailstone ever recorded, the size of a volleyball, fell in Vivian, South Dakota on July 23rd, 2010. Large hailstones often shatter windshields, destroy crops, and can even smash through roofs. And while hail might not terrify you in the same way a tornado or earthquake does, each year hailstorms cause between $10 and $20 billion across the U.S.