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(469) 598-0899The storm passes, the hail on the patio is about the size of a pea or a marble, and the natural conclusion is that the roof is fine. Often it is. But the size of the hail on your patio is only one part of the answer, and research on smaller hail has changed how roofers and insurers think about it.
TL;DR
Weather services classify hail as severe once it reaches 1 inch, about the size of a quarter, and that is the size at which damage to a typical asphalt shingle roof becomes a real concern. Smaller hail is not harmless. Research from the Insurance Institute for Business and Home Safety found that frequent sub-severe hail, under 1 inch, knocks granules off shingles and speeds up their aging, and that roofs exposed to weathering and two simulated sub-severe hail events became up to ten times more susceptible to damage from later large hail.
Whether a given storm damaged your roof depends on the size of the stones, the wind driving them, how long it lasted, and how old the roof already was. A pea-sized storm on a new roof is rarely a claim. Quarter-size and larger, or small hail on an older roof, is worth an inspection.
What Size Is Considered Severe Hail?
Severe hail is hail 1 inch in diameter or larger. The National Severe Storms Laboratory’s guide to hail basics describes quarter-size hail, 1 inch across, as the point at which hail is considered severe, and its thunderstorm guide lists hail one inch or greater as one of the conditions that makes a thunderstorm severe.
The same guide gives the familiar comparison sizes used in storm reports:
| Comparison | Diameter | What it usually means for a shingle roof |
|---|---|---|
| Pea | 1/4 inch | Rarely damages shingles on its own |
| Mothball | 1/2 inch | Can dislodge granules, especially on older roofs |
| Penny | 3/4 inch | Granule loss; possible damage on aged shingles and soft metal |
| Nickel | 7/8 inch | Borderline; age and wind start to decide it |
| Quarter | 1 inch | Severe; damage to shingles becomes a real concern |
| Ping pong ball | 1 1/2 inch | Damage to many standard shingles is likely |
| Golf ball | 1 3/4 inch | Widespread damage likely on standard shingles |
| Tennis ball | 2 1/2 inch | Serious damage, including to many impact-resistant products |
The diameters come from NSSL. The right-hand column is our trade reading of what each size tends to do to asphalt shingles, not a rule, because the next sections explain why the same size can do very different things.
Why Size Is Not the Only Thing That Matters
Two hailstones of the same size can hit a roof with very different force, and two roofs can take the same hit very differently.
Wind turns small hail into sideways hail
NSSL notes that when surface winds are strong enough, hail can fall at an angle or even nearly sideways, and that wind-driven hail can tear up siding and break windows. On a roof, wind-driven hail strikes the slope facing the storm much harder than the far side. A storm with modest hail and strong wind can damage one side of a roof and leave the other untouched.
Speed rises with size
The laboratory’s guide also gives expected fall speeds. It puts hail under 1 inch at roughly 9 to 25 mph, hail of 1 to 1.75 inches at about 25 to 40 mph, and hail of 2 to 4 inches at about 44 to 72 mph, with wide uncertainty from shape, melting, and wind. A larger stone is heavier and faster at the same time, which is why damage climbs so steeply once hail passes an inch.
Duration and density
A short burst of small hail is different from twenty minutes of it. The more stones that hit the same area, the more granules come off and the more likely a weak spot gets hit twice.
This is also why neighbors a few streets apart often compare notes and find completely different results. Hail falls in swaths, not evenly, and a storm that dropped a few scattered stones on one street can hammer the next one for several minutes.
The age of the roof
A new shingle is flexible and well covered in granules. A shingle that has spent fifteen Texas summers in the sun is harder and has already lost some of its protection. Hail that bounces off the first can bruise or crack the second.
What Small Hail Does to Shingles Over Time
This is where the newer research matters. The Insurance Institute for Business and Home Safety ran a multi-year program on impact testing of high concentrations of small hail, looking at sub-severe hail under 1 inch in diameter.
Its key findings, in its own terms:
- Repeated exposure to small hail can sharply reduce a roof’s resistance to later large hail events. The institute calls the damage cumulative.
- Subsevere hail knocks away protective granules, exposing the asphalt underneath to sunlight and weathering and speeding up aging.
- Roofs exposed to natural weathering and two simulated sub-severe hail events became up to ten times more susceptible to damage from later large hail impacts than new shingles.
- Current testing standards do not assess how performance holds up over time or against different concentrations and sizes of hail.
So small hail usually does not cause a leak on the day it falls. What it can do is shorten the roof’s life and set it up to fail in the next big storm.
What that means for a claim
Hail damage that shows up as gradual granule loss is harder to tie to a single storm than a clear bruise or crack. Insurers look for damage from a specific event. That is one more reason to have a roof looked at after any hailstorm large enough to leave hail on the ground, so the condition of the roof is on record before the next one.
How Often Does Hail Hit Collin and Denton County?
Often enough that hail is a regular part of owning a roof here. Our count of the NOAA Storm Events Database for 2021 through 2025 found 150 hail reports in Collin County on 38 separate hail days, and 234 reports in Denton County on 49 hail days.
Of the Collin County reports, 35 were of hail 1.75 inches or larger, golf ball size and up. The largest in the county in that period was 3.00 inches, reported near Plano on 20 April 2023. Denton County had 59 reports at 1.75 inches or larger, including a 5.90-inch stone near Sanger on 15 June 2023, recorded by a National Weather Service storm survey.
| County, 2021 to 2025 | Hail reports | Hail days | Reports 1.75 in or larger | Largest reported |
|---|---|---|---|---|
| Collin | 150 | 38 | 35 | 3.00 in |
| Denton | 234 | 49 | 59 | 5.90 in |
One caution. A report depends on someone seeing the hail and reporting it, so busier, more populated areas log more reports. These numbers count reports, not how often hail falls on your particular street. They do show that severe hail is a regular part of life here, not a once-a-decade event.
How to Judge a Storm That Just Passed
After a storm, you can tell a lot from the ground without climbing anything.
- Measure a few stones if any are still on the ground, or compare them to a coin.
- Look at soft metal: gutters, downspouts, the air conditioning unit, and the mailbox. Dents and spatter marks show hail hit with force.
- Note which side of the house took the storm, from damage to screens, siding, or plants.
- Check the gutters and the ground below downspouts for a heavy wash of granules.
- Write down the date and time.
The Insurance Institute for Business and Home Safety’s guide to identifying hail damage makes the same point about soft metal: dents and spatter marks on air conditioning units, gutters, metal flashing, and downspouts are collateral evidence that confirms a hail event occurred.
It also warns about look-alikes. Granule loss along shingle edges, uniform wear, manufacturing defects, and marks left during installation are not hail damage, and heavy rain alone can knock some granules loose. Our post on telling hail damage from roof wear goes through those differences in detail.
Impact Resistant Shingles and Small Hail
If small hail wears shingles down over time, it is fair to ask whether an impact-resistant shingle solves the problem. It helps, with a caveat.
Impact-resistant shingles are designed to take larger hail without cracking, and the IBHS FORTIFIED Roof standard’s optional Hail Supplement requires shingles rated Good or Excellent on the institute’s own impact ratings, which it says better protect a home from hail up to 2 inches in diameter. That is real protection against the storms most likely to cause a claim.
The caveat comes from the same research body. IBHS’s short-term roof aging work reports that natural weathering over the first year or two can measurably reduce the hail impact performance of impact-resistant shingles, and that repeated hail exposure can speed that decline. A tougher shingle starts ahead and stays ahead, but it still ages.
For a North Texas homeowner, the practical reading is simple:
- An impact-resistant shingle is worth considering when the roof is replaced anyway
- It does not make the roof immune to small hail wearing it down over the years
- It is still worth having the roof checked after bigger storms
Hail and the Rest of the House
Small hail that leaves the roof looking fine can still mark other parts of the house, and those marks are useful evidence.
NSSL notes that wind-driven hail can tear up siding and break windows. Even without much wind, soft materials show hail first. Aluminum gutters and downspouts dent. Air conditioning fins flatten. Painted wood trim chips. Vinyl siding can crack in cold weather when it is stiffer.
| Where to look | What hail leaves |
|---|---|
| Gutters and downspouts | Round dents, often in a line along the top edge |
| AC condenser | Flattened fins on the side facing the storm |
| Window screens | Small tears or dents in the frame |
| Siding and trim | Chips, cracks, or spatter marks |
| Fence and deck | Fresh splits or bright spots on weathered wood |
If the siding took hits, our post on identifying hail damaged siding in Texas covers what to look for on each siding type.
When Small Hail Is Worth an Inspection
Not every hailstorm needs a roofer. These are the situations where it does.
| Situation | Worth an inspection? |
|---|---|
| Pea-sized hail, new roof, no dents on metal | Usually not |
| Pea to penny size, roof over ten years old | Worth a look, especially with granules in the gutters |
| Quarter size or larger | Yes |
| Any size with strong wind | Yes, check the windward slopes |
| Dents or spatter on gutters, vents, or the AC unit | Yes |
| A leak or ceiling stain after the storm | Yes, promptly |
If hail did damage the roof, the manufacturer’s shingle warranty is rarely the answer. Warranties such as Atlas Roofing’s current residential limited warranty list hailstorms among the acts of God they do not cover. Hail damage is a homeowners insurance matter, and our guide to what to do after hail damages a roof in North Texas covers the first steps.
Have the Roof Checked After the Next Hailstorm
If hail has passed over your home in Prosper, McKinney, Frisco, Anna, or anywhere across Collin and Denton County, and you are not sure whether the roof took damage, a free roof inspection will tell you. A proper inspection covers the shingles, the ridge, the soft metal and the vents, and should tell you plainly whether there is damage worth claiming.
If you are in Prosper, our Prosper roofing page covers local details. Anywhere else, call (469) 598-0899, or start with All Around Texas Roofing online.