A hailstone occurs during a thunderstorm, and it consists of ice. It's solid, and can be as big as a grape fruit, or it can just be as small as a pea, so it depends. They form in the clouds and they have some of the following effects : 1. It indicates that it will start to rain soon 2. the vertical winds will carry the raindrops to the coldest parts of the atmosphere 3. because of the climate they will turn the rain into hail or ice
