Lessons From The World’s First Indoor Hailstorm

Who would take the time to fashion hailstones from a mix of tap water and seltzer water in a special laboratory, and then fire them at a variety of roofs, windows and doors from air cannons? Isn’t that painstakingly detailed work?

Of course. But the scientists at the Insurance Institute for Business & Home Safety (IBHS) in Tampa, Fla., decided to do just that as part of a major study to help homeowners, manufacturers of home products and others better cope with this natural disaster.

Orchestrating an indoor hailstorm

The IBHS has a huge indoor facility measuring a half-acre across and 70 feet high at its existing research center in South Carolina. It sent scientists into the field to study hailstorms in six states to gather a variety of data, as hail varies in size, shape and hardness. Then, in February, after creating hailstones that closely mimics those produced by Mother Nature, it orchestrated the first-ever full-scale indoor hailstorm.

Within a four-minute time span, the IBHS used ice and air cannons to fire 9,000 pieces of man-made balls of ice (some as large as 2 inches in diameter) at top speeds of 76 mph at a test house featuring different roofing and siding materials, windows, and doors, along with a car and outdoor furniture to replicate a residential setting.


IBHS Hailstorm Demonstration Highlights from IBHS on Vimeo.


The goal was to achieve conditions present in a typical super-cell thunderstorm known to produce hail. While IBHS has only begun to analyze the results, it has found that the damage was confined mostly to roofs, and particularly to soft areas with less coverage, similar to what researchers found during “real” outdoor hailstorms in the field. This spring, the Institute is collecting more data, and it plans to bring back damaged housing parts to its research center to determine their longevity once hail has wrecked havoc.

Spring Means Hail Season

Hailstorms are common in the spring, because of the season’s frequency of thunderstorms with strong, tilted updrafts, which are known for producing hailstones–some as big as marbles and balls. But they can happen anywhere, and at any time.

According to the IBHS, the U.S. experiences more than 3,000 hailstorms a year, resulting in more than $1 billion in damages. “Hail Alley” — which runs from Texas north through the middle of the country to the Dakotas — is particularly prone.

Hail Preparedness Tips for Homeowners

So, what can you do to prepare for the next hailstorm? According to the IBHS, you should consider these precautions:

  • As soon as a hailstorm starts, if it’s safe, move vehicles under cover and move outdoor furnishings indoors.
  • During a hailstorm, stay indoors and stay clear of windows; they may break.
  • After a hailstorm, inspect your property for signs of hail damage; snap photos to document the impact.
  • If you plan on a replacing a roof, the IBHS recommends using materials that are “impact resistant,” specifically those with a Class 4 rating from Underwriters Laboratories’ 2218 standard. (Siding, window and door products aren’t yet graded this way.)
  • Be sure to hire a reputable contractor. Before you hire anyone, check references; ask for proof of certification or licensing, and be sure they’re bonded and insured, too. “Some ‘storm chasers’ are not reputable, demanding money up front, then disappearing,” says Julie Rochman, president and CEO of the IBHS.

It can also be a good idea to stay on top of changing weather. Sign up for email or text weather alerts, or get a weather radio, to alert you to emerging weather hazards and reports of hail in your community.


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