Science behind hail formation

Published: Apr. 12, 2023 at 12:24 PM CDT
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QUAD CITIES, Iowa/Ill. (KWQC) - Hail causes billions of dollars in damage to homes, crops and vehicles each year in the United States.

There were three separate hail disasters in the u-s just last year that totaled more than $1 billion dollars in losses.

The hail that moved through the Quad Cities area during the morning hours of April 4 ranged from the size of quarters, to tennis balls and baseballs.

Why are some hailstones larger than others? It all has to do with temperature and how strong the winds are in the updraft of a thunderstorm.

The updraft is the warm, moist air that rises 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.

The stronger the winds are coming into the storm leads to a larger hail stone.

Hail can be the size of peas or nickels, to as large as a grapefruit (4.5 inches in diameter).

Severe hail is one inch in diameter, about the size of a quarter, and it requires an updraft wind speed of at least 50 mph.

Golf ball to baseball size hail require updraft speeds of 65 to 80 miles per hour.

The largest hail stone on record in the US was 8 inches in diameter, occurring in Vivian, South Dakota. The hailstone weighed in at nearly two pounds.