WHY DOES HAIL FORM?

Hail forms when the winds in a storm called updrafts are strong enough to push through the freezing level of a storm.  If an updraft extends far above the freezing level, then raindrops and water vapor can freeze. Frozen water droplets can blow around to different parts of a storm, and accumulate more water and re-freeze many times before it is heavy enough to fall to the ground.