Understanding Hail Size: What Different Sizes of Hail Do to Your Roof

Not all hailstorms are equal. A storm that drops pea-sized hail is a very different event from one that drops golf balls. The size of the hailstones determines the type and severity of damage your roof will sustain, and knowing what to expect at each size level helps you make informed decisions about inspections, repairs, and insurance claims.

This guide breaks down exactly what different sizes of hail do to residential roofing materials, references the measurement standards used by NOAA and the National Weather Service, and explains how to find out what size hail has actually hit your address.

How NOAA Measures and Reports Hail Size

The National Oceanic and Atmospheric Administration (NOAA) is the authoritative source for severe weather data in the United States. NOAA and the National Weather Service (NWS) use standardized reference objects to describe hail size in storm reports. This creates a consistent language that meteorologists, insurers, and homeowners can all understand.

NOAA Hail Size Reference Chart

Here are the standard reference objects and their corresponding measurements:

Pea: 0.25 inches (6 mm). The smallest commonly reported size.

Marble: 0.50 inches (13 mm). Still small, but starting to cause cosmetic issues on certain materials.

Dime: 0.75 inches (19 mm). Approaches the threshold for roof damage.

Penny/Nickel: 0.75 to 0.88 inches (19 to 22 mm). Beginning of potential functional damage on vulnerable materials.

Quarter: 1.00 inch (25 mm). The NWS threshold for "severe" hail. This is where meaningful roof damage begins.

Half dollar: 1.25 inches (32 mm). Significant damage likely on standard roofing.

Golf ball: 1.75 inches (44 mm). Major damage expected on most residential roofing materials.

Tennis ball: 2.50 inches (64 mm). Severe damage to roofs, vehicles, and structures.

Baseball: 2.75 inches (70 mm). Catastrophic damage to most exterior surfaces.

Softball: 4.25 inches (108 mm). Extremely destructive. Can penetrate roofing materials entirely.

The NWS classifies any hail of 1.00 inch (quarter-sized) or larger as "severe." This is the threshold at which the NWS issues severe thunderstorm warnings and the size at which significant roof damage becomes likely.

Quarter-Sized Hail (1 Inch): Where Damage Begins

Quarter-sized hail is the starting point for real roof damage. At 1.00 inch in diameter, these stones carry enough kinetic energy to begin affecting most residential roofing materials, particularly if the roof is older or already weathered from previous storms.

What It Does to Asphalt Shingles

Standard three-tab asphalt shingles are the most vulnerable. Quarter-sized hail can knock loose the protective granule coating on the surface of the shingles, exposing the asphalt mat underneath. This granule loss may not look dramatic, but it accelerates aging and deterioration.

You might notice dark spots or bare patches where granules have been stripped away. Gutters and downspouts may contain an unusual amount of granule sediment after the storm. These are signs that the hail was large enough to start degrading your shingles, even if no cracks or breaks are visible.

On newer architectural shingles (also called dimensional or laminate shingles), quarter-sized hail may cause less visible damage. However, repeated exposure to stones of this size over multiple storms has a cumulative effect.

What It Does to Other Materials

Metal roofing. Quarter-sized hail typically leaves small dents or dimples on standing seam and corrugated metal panels. While cosmetic, these dents generally do not compromise the roof's waterproofing integrity.

Tile roofing. Clay and concrete tiles can crack or chip from quarter-sized hail, particularly if the tiles are older or have pre-existing hairline fractures.

Wood shingles and shakes. Splits and cracks can develop from repeated impacts, even at this relatively modest size.

Should You Worry?

A single storm with quarter-sized hail may not require immediate action, particularly if your roof is relatively new and in good condition. However, if your area has been hit by multiple storms with hail of this size or larger, the cumulative damage could be significant. Check your address on HailScore to see how many storms have impacted your property and how large the hail was.

Golf Ball-Sized Hail (1.75 Inches): Major Damage Expected

Golf ball-sized hail represents a significant escalation. At 1.75 inches in diameter, these stones are nearly twice the diameter of quarter-sized hail, but because volume scales with the cube of the radius, a golf ball-sized hailstone has roughly four to five times the mass of a quarter-sized one. That means dramatically more impact energy.

What It Does to Asphalt Shingles

Golf ball-sized hail causes obvious, functional damage to most asphalt shingles. Impact marks appear as clearly visible circular bruises or divots. The protective granule layer is stripped away in concentrated areas, and the asphalt mat underneath may be cracked or fractured.

Shingle edges and corners are particularly vulnerable. You may see shingles that are cracked through, with pieces broken off entirely. The seal strip that bonds overlapping shingles can also be broken, allowing shingles to lift in subsequent winds.

After a storm with golf ball-sized hail, most roofing professionals would recommend a thorough inspection and potentially a full roof replacement, depending on the age and condition of the roof.

What It Does to Other Materials

Metal roofing. Golf ball-sized hail creates noticeable dents in most metal panels. On thinner gauge metal, the dents may be deep enough to compromise the panel's structural profile and potentially affect waterproofing at seams and fastener points.

Tile roofing. Cracking and breaking become much more common at this size. Individual tiles may shatter on impact, requiring spot replacement or full sections of new tile.

Impact-resistant (Class 4) shingles. This is where Class 4 shingles prove their value. These materials are specifically engineered to withstand impacts from a 2-inch steel ball without cracking, which means golf ball-sized hail (1.75 inches) falls within their designed protection range. Damage is typically minimal, and the shingle's waterproofing integrity is maintained.

What You Should Do

If your area experiences golf ball-sized hail, schedule a professional roof inspection as soon as possible. Do not try to assess the damage from the ground alone. Many impacts will only be visible from on the roof itself. Document everything with photos before making any repairs, and report the damage to your insurance company promptly.

Your HailScore report will show the specific hail sizes recorded near your address from NOAA data, helping you verify that the storm produced golf ball-sized stones at your location.

Baseball-Sized Hail (2.75 Inches): Catastrophic Impact

Baseball-sized hail is a catastrophic weather event. At 2.75 inches in diameter, these hailstones can weigh over half a pound and fall at speeds exceeding 80 miles per hour. The kinetic energy involved is enough to cause severe damage to virtually any residential roofing material.

What It Does to Asphalt Shingles

Baseball-sized hail tears through standard asphalt shingles. Large sections of shingle material can be completely removed or shattered on impact. The underlayment beneath the shingles is frequently punctured or compromised, creating immediate pathways for water infiltration.

This level of impact typically requires a full roof replacement, not just repairs. The damage is usually extensive enough that spot patching is not a viable long-term solution.

What It Does to Other Materials

Metal roofing. Deep dents, creased panels, and potential punctures at impact points. Even heavier gauge metal panels can be deformed significantly by hailstones of this size.

Tile roofing. Widespread shattering of clay and concrete tiles. Most tile roofs will need significant section replacement or full re-roofing after exposure to baseball-sized hail.

Impact-resistant (Class 4) shingles. Even Class 4 shingles may show damage at this size, though they will generally perform significantly better than non-rated materials. The 2-inch steel ball test used for Class 4 certification is smaller than baseball-sized hail, so some damage should be expected.

Skylights and windows. Baseball-sized hail frequently shatters skylights and can break residential window glass, particularly older single-pane windows. If your home has skylights, inspect them carefully after any storm with hail of this size.

What You Should Do

After a storm with baseball-sized hail, assume your roof needs professional inspection immediately. Check for interior leaks, water stains on ceilings, and any signs that water has penetrated the roof structure. File your insurance claim right away and document every detail.

If you notice active leaks, arrange for emergency tarping to prevent further water damage. Most insurance policies cover reasonable temporary repairs to protect the structure.

Softball-Sized Hail (4.25 Inches): Extreme Destruction

Softball-sized hail is the most destructive form of hail that falls in the United States. At 4.25 inches or more in diameter, these stones can weigh over a pound and impact at speeds exceeding 100 miles per hour. Events producing hail of this size are rare, but Colorado has recorded multiple instances, particularly along the eastern Front Range and into the High Plains.

What It Does

At this size, the question shifts from "what did the hail damage" to "what did it spare." Softball-sized hail can punch completely through roofing materials, shatter roof decking, and even damage structural framing. Asphalt shingles are destroyed. Metal panels are punctured. Tile roofs disintegrate on impact.

Vehicles are totaled. Siding is demolished. Trees are stripped of branches. Softball-sized hail is a total loss event for most exterior surfaces.

Historical Context

Colorado has a documented history of extreme hail events. NOAA records include multiple reports of four-inch-plus hailstones along the Front Range and eastern plains. While these events are uncommon, they are not unprecedented. The state's geography, where warm moisture from the Gulf collides with cold air descending from the Rockies, creates ideal conditions for the powerful supercell thunderstorms that produce the largest hail.

What You Should Do

After an event of this magnitude, safety is the first priority. Check for structural damage to your home, avoid areas where the roof may be compromised, and contact your insurance company immediately. Emergency repairs to prevent water intrusion should be your first physical action.

These events typically trigger community-wide insurance responses and may involve FEMA or state emergency management depending on the scale of damage.

How Hail Size Affects Different Parts of Your Home

Hail damage is not limited to your roof. Understanding how different sizes affect other components helps you conduct a thorough post-storm assessment.

Gutters and Downspouts

Aluminum gutters show dents from hail as small as 0.75 inches. At 1.00 inch and above, denting becomes significant enough to affect water flow. Golf ball-sized hail can deform gutter profiles and knock sections loose from their mounting hardware.

Gutter damage is actually one of the easiest indicators of hail severity. Because gutters are exposed and made of soft aluminum, they record hail impacts very clearly. If your gutters are heavily dented, your shingles likely sustained similar or worse impacts.

Siding

Vinyl siding cracks and breaks when hit by hail 1.00 inch or larger. Fiber cement siding is more resistant but can chip and crack at golf ball size and above. Wood siding dents and splinters progressively with increasing hail size.

Windows and Screens

Window screens are easily damaged by even small hail. The screens themselves are not expensive to replace, but damaged screens indicate that the storm produced hail with enough energy to affect other surfaces. Window glass can crack or break from golf ball-sized hail and above, particularly older or single-pane windows.

HVAC Equipment

Outdoor air conditioning condensers and heat pump units are vulnerable to hail damage. Bent condenser fins reduce efficiency, and severe impacts can damage internal components. Check your outdoor HVAC equipment after any significant hailstorm.

Cumulative Damage: Why Multiple Storms Matter More Than One

One of the most important concepts for Colorado homeowners to understand is cumulative hail damage. A single storm with quarter-sized hail may not cause obvious problems. But if your address has been hit by five, ten, or fifteen storms with hail of one inch or larger over the past decade, the cumulative effect is significant.

Each impact loosens more granules, widens existing cracks, and weakens the bond between shingle layers. A roof that survived its first few hailstorms may fail during a relatively modest event because the previous storms had already compromised its integrity.

This is exactly why knowing your hail history matters. NOAA has been collecting detailed storm data for decades, and HailScore makes that data accessible for any address in the country. Your HailScore report analyzes over 10 years of records across four dimensions: storm frequency, hail size, recency, and proximity. Together, these dimensions paint a complete picture of your property's hail exposure.

Check your address on HailScore to see exactly what size hail has hit near your home and how many times. Think of it like a Carfax for your roof. Just as you would want to know a car's accident history before buying it, you should know your roof's storm history before investing in repairs, replacement, or a home purchase.

What to Do After Any Hailstorm

Regardless of the reported hail size, take these steps after every significant storm:

Check for visible damage from the ground. Walk around your property and look at gutters, siding, window screens, and any exposed surfaces.

Document everything with time-stamped photos before any cleanup or repairs begin.

Review your HailScore report to see the NOAA-confirmed data for the storm, including reported hail size and proximity to your address.

Schedule a professional inspection if hail was 1.00 inch or larger. Roof damage from quarter-sized hail and above often requires professional eyes to properly assess.

Report to your insurance company if the damage warrants a claim. Do not delay. Colorado policies typically require prompt reporting.

For hail damage specific to your city, check your local HailScore page. We cover cities across Colorado, including Denver, Colorado Springs, Aurora, and Fort Collins, with data from NOAA's storm event database.

Understanding hail size is not just meteorological trivia. It directly determines whether your roof survived a storm or needs attention. Know the sizes, know your history, and know when to act.