The higher this cloud belt, the larger the hailstone
This hail is formed during a summer storm and cannot be compared to winter hail, which is actually supercooled rain (frozen raindrops.)
Often this comes down in the form of dust hail.
During a thunderstorm, there is a large potential difference between the earth and the cloud, which gives rise to a lightning bolt (discharge).
There is no noticeable difference in potential with winter hail.