What’s interesting is how varied in size and shape that hail and be, especially with what San Antonio saw on Tuesday night.
What’s happening in the atmosphere during a hail storm? How does hail form and what makes it change shape?
It’s all determined by the rotations inside the thunderstorm. There’s a tremendous amount of updraft in a supercell thunderstorm that towers upwards of 60,000 feet. That updraft keeps ice airborne. It continues to collect ice as it rotates and moves around the top of the thunderstorm.
Temperatures are below freezing in those cells, so it’s easy for hail to get bigger and bigger like the ice that we saw from viewers on Tuesday night.
Gravity takes over and, on its descent to the ground, especially in windy conditions, the hail will take its shape.