Hail size 1"
1 E Knoxville Marion County
“(DMX)”
— NOAA / SPC storm report
/ Storm field report · Marion
Hail in Knoxville · Apr 17, 2026
NEXRAD logged 17 hail signatures up to 1.5"; the estimated-size surface reached 0.75" aloft. Open it on the live map to see the swath over the streets.
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Peak hail signal 1.5" ≈ ping-pong ball · the largest NEXRAD radar signature
Homes in the hail footprint 840
Ground reports 1 1 hail
Radar surfaces 2 NEXRAD + estimated size
Convective day · Apr 17, 2026 · noon–noon UTC
Severity
The 5th most severe storm Knoxville has seen in the last 12 months
Composite score · 4.0 / 10
Storm severity score
Overview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
4.0 /10
- Peak hail signal
- 38 /100
- Homes exposed
- 58 /100
- Ground truth
- 17 /100
Largest radar-indicated size — a signal of damage potential, not confirmation.
How many homes sit inside the storm's footprint.
Independent storm reports filed with the NWS.
Evidence / storm surfaces
How Knoxville saw the hail — from two instruments
Apr 17, 2026 · Knoxville, IA
Two instruments, one storm: NEXRAD logs the point signatures it detected overhead, while the estimated-size surface models how large the hail aloft could have grown. Agreement between them is not guaranteed — the gaps are where the model ran ahead of, or behind, the detections.
NEXRAD radar signatures Surface resolved
Radar signature field NEXRAD's hail signatures for this storm: the spots the radar detected from above. A detection overhead is not the same thing as a confirmed stone below.
Max size
1.5"
Detections
17
Radar-estimated hail size Surface resolved
Estimated size field Radar-estimated maximum hail size across the swath, modeled from radar aloft. It reflects the biggest stone the storm could support, which may differ from what actually fell.
Max size
0.75"
The storm in context
Where Apr 17, 2026 sits in Knoxville's hail record.
This was Knoxville's 1st recorded hail day — the first hail day in our records for the city. By severity it ranks 5th of the 11 storms we have logged here. Radar put the day's largest stone over Knoxville at 1.5" — the largest NEXRAD radar signature.
The Apr 17, 2026 convective day was bigger than Knoxville: the same system put hail over 1,016 other tracked cities, 201 of them in Iowa. Nearest: Tracy (5 miles east, up to 2"); Hamilton (7 miles south, up to 1.25"); Leighton (12 miles northeast, up to 2.5").
These maps are stills. In the app this date is one of 11 Knoxville storm dates on a live map — both surfaces, the reports, and a replay — and the same map is where you draw the swath. This page rebuilds nightly.
Ground reports
What people on the ground reported
1 report filed with the NWS
These are storm reports filed with the National Weather Service and released through the NOAA Storm Prediction Center — public-domain observations from spotters, the public, and NWS surveys. We quote each one exactly as filed.
Hail reports
1 reportHigh damage potential
What 1.5" hail means for Knoxville roofs.
Hail around an inch and a half is capable of cracking shingles, stripping granules, and denting gutters, vents, and siding. Risk is usually greatest near the strongest radar signal, but property-level damage still requires an on-site inspection.
Radar reading · not confirmed damage
Roofing exposure
What this storm is worth to a roofer.
840 homes × $12,000 avg. claim
Potential roof exposure
$10M
Potential roof exposure — 840 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
- Illustrative jobs
- 4 jobs
- Illustrative work
- ~$60K
Close just 0.5% of the 840 homes in this footprint at the average $15,000 roof job. Illustrative math, not a projection — your results depend on your outreach and how the market responds.
Claim window
April 2028
Claims from this storm can typically be filed until around April 2028 — the window to reach these homeowners while it's still open. Deadlines vary by policy and state.
Names and phones for every home in the footprint: at most $176 on top of the $150 plan.
Knoxville hail history
Other storms in Knoxville.
11 recorded storm days in Knoxville, IA
Map unavailable
NEXRAD surface Storm date Knoxville / IA
Sep 8, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
Aug 13, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
Aug 12, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
Jul 20, 2026
1.75" Estimated 1.75"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
Jul 3, 2026
1.75" Signatures 1.75" Estimated 0.75"
1 ground report Open report →
Estimated-size surface Storm date Knoxville / IA
Jun 11, 2026
2.75" Estimated 2.75"
7 ground reports Open report →
Estimated-size surface Storm date Knoxville / IA
Jun 10, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
Jun 5, 2026
2.5" Signatures 2.5" Estimated 2"
5 ground reports Open report →
Estimated-size surface Storm date Knoxville / IA
May 18, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Knoxville / IA
May 15, 2026
1" Signatures 1" Estimated 0.75"
No ground reports filed Open report →
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A storm day here is a convective day — it runs from noon to noon
UTC, so late-night hail is grouped with the afternoon storm that
spawned it rather than split across two calendar dates. Ground
reports are public-domain observations from the NOAA Storm
Prediction Center. Radar tells you where to look. Only an inspection confirms damage at an address. Last updated Sep 9, 2026.