Typically, the swirl of stormy weather obscures the cells at the heart of severe thunderstorms. This uncommonly clear view of an entire thunderstorm cell, with the top of the growing cumulonimbus tower topping out at 40,000 feet, reveals many interesting features, including “fall streaks” of what may be hail from the underside of the overhanging anvil portion of the cloud. Shortly after this photo was taken on May 22, 2011, near Madison, the storm pelted the Sun Prairie area with large, damaging hail. More
Hail is precipitation in the form of large balls or lumps of ice that grow in thunderstorms and other severe convective storms. Hailstones begin as small ice particles that grow primarily by accretion; to grow large, they require abundant water droplets. As the hailstone moves up and down through a storm, it collides with water droplets and grows steadily larger.