With winds in different directions, blowing at different speeds, clouds grow and decay over and over throughout the course of a day. When a system of clouds becomes organized, and keeps growing, it can develop into a thunderstorm. High winds are often associated with severe storms. Actually, these storms feed off the high winds created by the collision of two different air masses, the difference in two pressures, and the jet stream, a column of air flying by overhead at several hundred miles per hour. Hail is a dangerous and destructive element often associated with severe storms.
Sleet is often mistaken for hail, however the two are different.
Sleet is the result of rain falling through a very cold atmosphere and freezing before it hits the ground. Hail is formed within the high tops of a well organized thunderstorm. An updraft will sometimes throw rain droplets high up into the tops of a cloud. Here, the temperature is well below freezing, and the droplet freezes. The droplet then falls and can become caught in another updraft.