Dented gutters and downspouts: reading the record a hailstorm leaves

What a trained inspector looks for

The Insurance Institute for Business & Home Safety publishes survey practices for roof inspections as part of its RICOWI roof guide. Gutters appear in its list of roof assembly components to evaluate, along with edge flashing, fascia and the roof covering. For hail, the guide directs the surveyor to:

• Evaluate spatter marks, the spots where hail knocked off the oxidation film or coating, recording their size, direction and shape.
• Evaluate dents, recording their size and direction.
• Compare materials that were damaged with those that were not, and document which patterns are typical of hail.
• Flag patterns atypical of hail, which could come from aging and weathering, accidental mechanical damage such as fallen limbs or dropped tools, or intentional damage. The guide lists repeated marks of the same size, shape or depth, well-defined edges and damage in areas hail could not reach as signs of intentional damage.

Before going on site, the same guide has surveyors pull storm reports from NOAA's National Centers for Environmental Information, the Storm Prediction Center and the National Weather Service. Its equipment list includes a small ruler or scale for photographs, a habit worth copying when you photograph your own gutters.

What you can check from the ground

State insurance regulators give homeowners a few ground-level clues. Nebraska's Department of Insurance notes that a significant amount of shingle granules at the end of downspouts may point to roof damage, and that hail strong enough to damage a roof will also damage nearby cars, wood fences, shutters and siding. It suggests giving the adjuster a written list of other items that appear damaged, such as windows, siding and fascia.

Wisconsin's Office of the Commissioner of Insurance, in its after-the-storm guidance, tells policyholders to photograph damage, list damaged items for the adjuster, and not throw out damaged property without the adjuster's agreement. That last point matters for gutters: a dented section pulled down by a helpful neighbor is evidence you no longer have.

Evidence, not a verdict

Hail-pattern dents on a gutter show that hail struck the house. They do not by themselves prove the shingles failed; the IBHS guide notes that signs of hail damage vary by roof type, and metal trim is not the roof covering. That is why the IBHS method compares damaged and undamaged materials rather than reasoning from one component. Insurers work the same way; Michigan's insurance department notes that when hail and wind lift shingles, a homeowners policy covers only the damaged portion of the roof, and the insurer is not required to replace the whole roof, according to its severe storm guidance.

How NOAA logs hail, and what the sizes mean

The National Weather Service's Storm Data instruction has every hail report of three-quarters of an inch or larger entered in the record, with 1 inch as the minimum for severe hail. Its conversion table pairs sizes with familiar objects: a penny is 0.75 inch, a quarter 1 inch, a ping pong ball 1.5 inches, a golf ball 1.75 inches and a lime 2 inches. The instruction encourages spotters to measure rather than estimate, and it discourages "dime-size" and "marble-size" because those objects vary.

Which counties get hit most often

These figures from NOAA's Storm Events Database cover 2016 through 2025.

Dane County also leads Wisconsin in hail of 1 inch or larger, with 152 events. Hennepin County logged more golf-ball-size or larger events than Dane, 33 to 25, including a 3-inch stone in Minneapolis on August 11, 2023 for which the database lists $5 million in property damage.

When the hail comes

Statewide hail events by month over the same decade, with each state's busiest month in bold:

Wisconsin's season runs long, with 273 events in September. A fall walk around the house, looking up at the gutters, catches damage from the late storms before snow hides it.

Documenting it for a claim

Photograph dents with a ruler in the frame, note the date, and look the storm up in the NOAA database. The National Roofing Directory's guides to documenting roof damage for a claim and why roof claims get denied cover the next steps. Recent storms are on the Wisconsin storm center and Michigan storm center. Winter's threat to the same gutters is on the ice dams page.

Frequently asked questions

Do dented gutters mean my roof has hail damage?

Not necessarily. Hail-pattern dents show that hail struck the house, and they are worth photographing, but shingles respond differently from metal. The IBHS survey method compares damaged and undamaged materials across the property before drawing conclusions about the roof.

How can an inspector tell hail dents from other dents?

The IBHS survey practices record the size and direction of dents and spatter marks and look at the overall pattern. Repeated marks of identical size and depth, sharp tool-like edges or damage in places hail could not reach point to something other than hail.

What size hail is considered severe?

One inch in diameter, about a quarter, under the National Weather Service's Storm Data instruction. Reports of three-quarter-inch hail and larger are still entered in NOAA's database.

When is hail season in Wisconsin?

It peaks in May, with 532 statewide events in that month over 2016-2025, but stays active through September, which logged 273.