I photographed this pea-sized hailstone during a brief, but violent spring thunderstorm. It was just outside my side door, so I didn't even have to get wet! Hail forms when small pieces of ice get blown upward in large cumulonimbus clouds. The stronger the winds, the more often the ice pellet will rise and fall inside the cloud, and the larger the resulting hailstone will be. Large hailstones can cause severe damage and injure people.