Hailstones are balls or irregular lumps of ice that form during thunderstorms. They develop when strong updrafts in the storm carry water droplets high into the atmosphere, where temperatures are below freezing. As these droplets rise and fall, they freeze and accumulate layers of ice, eventually falling to the ground when they become too heavy. The size of hailstones can vary greatly, ranging from small pellets to larger stones that can cause damage. Hail is often measured using a scale that compares the size of hailstones to common objects, such as marbles or golf balls. Severe hailstorms can lead to significant damage to crops, vehicles, and buildings.