Hailstorms are caused by freezing, which is the process of water droplets in a thunderstorm cloud turning into ice. When there are strong updrafts of wind in a thunderstorm, they can carry water droplets upward into the colder regions of the cloud. The low temperature causes these droplets to freeze into ice pellets. As the ice pellets are carried by the updrafts, they can collide with other droplets and absorb more water. This process of freezing and water absorption continues until the ice pellets become too heavy for the updrafts to support, and they fall to the ground as hailstones. It is important to note that condensation, convection, and sublimation are not the direct causes of hailstorms, although they are associated with the formation and dynamics of thunderstorms.