The Probert Encyclopaedia of Science & Technology

HAIL

Hail is a precipitation in the form of pellets of ice, known as hailstones. It is caused by the circulation of moisture in strong convection currents, usually within cumulonimbus clouds. Water droplets freeze as they are carried upwards. As the circulation continues, layers of ice are deposited around the droplets until they become too heavy to be supported by the currents and they fall as a hailstorm.
Research Hail