What causes some thunderstorms to produce hail?
Hail forms when thunderstorm updrafts are strong enough to carry water droplets well above the freezing level. (The temperature of the atmosphere typically decreases with increasing altitude.) This freezing process forms a hailstone, which can grow as additional water freezes onto it. Eventually, the hailstone becomes too heavy for the updrafts to support it. The hailstone will melt as it falls through air that is above freezing. Some small hailstones will melt entirely and fall as rain, while others will remain chunks of ice as they hit the ground. Typically, the stronger the updraft in the storm, the larger the hailstone that can be produced. Learn more about hail formation on this USA TODAY resource page.
