A hailstorm usually occurs during the warm weather and is accompanied in many cases by thunder, lightning and rain. Hail is formed when raindrops freeze while passing through a belt of cold air on their way to earth.
Single raindrops form very small hailstones. It is interesting to note when a raindrop falls as a hailstone, it may meet with a strong rising current of air. so, it is carried up again to the level where the raindrops are falling. New drops begin to cling to the hailstone. And as it falls once more through the cold belt, these new drops spread into a layer around it and freeze, and now we have larger hailstones.
This rising and falling of the hailstone may be repeated time after time until it has added so many layers that its weight is heavy enough to overcome the force of the rising current of air. Now it falls to the ground.
Hailstones measuring three or four inches in diameter and weighing as much as a pound are sometimes built up. Snow too freezes around hailstones when they are carried into regions where it is forming. Thus, the hailstones are frequently made up of layers of ice and snow.
Hailstorm in Bogota, Colombia
On 20 April 1888 in Moradabad, India, 246 people (along with more than 1,600 sheep and goats) were killed by hailstones, some as big as cricket balls. Hailstones can be a dangerous hazard, especially if they get very large. They can do tremendous damage to property and have even been know to kill cattle!