Science of hail formation: Why are some hailstones larger than others?

Published: Aug. 17, 2023 at 1:34 PM CDT
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QUAD CITIES, Iowa/Ill. (KWQC) - Thunderstorms quickly developed ahead of a cold front Thursday morning, producing brief heavy rain and even hail in some locations.

Most of the storms developed east of the Mississippi River. Some parts of Davenport saw no rain at all, while portions of Rock Island, Moline and East Moline saw heavy rain and dime size hail.

One storm in particular moved through Mercer and Henry counties in Illinois, producing quarter to golf ball size hail.

The size of the hail has to do with the updraft of the thunderstorm.

The updraft is the wind that takes warm, moist air rising into the thunderstorm.

Updrafts then lift frozen water droplets higher into the cloud, where temperatures are well below zero.

Ice continues to layer up as the strong wind lifts the droplets up and down, higher into the cloud.

Eventually the weight of the hailstone exceeds the force of the updraft and the hailstone falls to the ground.

Simply put, the stronger the updraft leads to a larger hailstone.

Watch the video above to see some of the hail that fell on the morning of August 17, and the specific sizes of hail in relation to the strong updraft wind speeds.