Hail Demo: Mother Nature’s Million Dollar Babies

Hail-Ad-3_IBHSWhen frozen balls of ice rain down from thousands of feet above your head, the result can be damaging and sometimes dangerous. A single hailstorm can cause $1 billion or more in property damage, according to insurance industry estimates. Mastering the art of creating an indoor hailstorm – something that has never been done before – gives IBHS Research Center staff the unique opportunity to find ways to strengthen properties against Mother Nature’s costly menace.

Making Real Hail

IBHS researchers have been working since 2010 to develop realistic hailstones for impact testing, which will be on display during the first public demonstration of these capabilities on Wednesday, February 20 as national media and other representatives gather at the IBHS Research Center in South Carolina. Making realistic hailstones presented many challenges – it is a lengthy, labor-intensive process.

After many experiments to match correct density and hardness, researchers settled on two methods to make hailstones in the IBHS lab.  The first method is compacting crushed ice into spheres. The second method is based on injecting liquid into molds.  Using tap water, distilled water, and specific ratios of seltzer water, scientists can achieve desired hailstone densities.

Once the molds are filled, they are placed in freezers overnight. The following day, the molds are pulled from the freezers, and taken apart to remove the hailstones.  Each rubber mold is surrounded by a wooden case. This helps the mold keep its shape because the ice expands when it freezes. Finally, the stones are cleaned and removed from the rubber molds. They are carefully stored until just prior to test time. 

IBHS can now make more than 300 hailstones each day in six different sizes.  Researchers are working to automate the manufacturing process to increase the number of hailstones made each day, and to reduce the amount of labor required by staff.

On February 20, IBHS will use 8,000-10,000 hailstones during the demonstration that will test varying types of construction materials and other items commonly found on properties in hail-prone areas. Learn more about the hail demo

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Creating Mother Nature’s Million Dollar Babies


Hailstones sitting in a freezer at the IBHS Research Center.


The hardness of a hailstone is tested at the IBHS Research Center.


Hailstones created at the IBHS Research Center are shown.


IBHS research engineers shape hail at the IBHS Research Center.


Hail is measured at the IBHS Research Center.


Dr. Tanya Brown, IBHS research scientist, measures hail at the IBHS Research Center.


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