Hail size 1"
Bethalto Madison County
“(LSX)”
— NOAA / SPC storm report
Hail in Alton May 3, 2026
Both radar surfaces caught this storm: NEXRAD logged 0 hail signatures up to 1.75", and the radar-estimated size reached 0.75" aloft.
Largest hailstone
1.75"
≈ golf ball · the largest NEXRAD radar signature Homes in the hail footprint
16,098
Ground reports
8
8 hailThe 2nd most severe storm Alton has seen in the last 12 months
Storm severity score
Overview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
6.2 /10
- Hail size
- 44 /100
- Homes exposed
- 84 /100
- Ground truth
- 100 /100
Largest hailstone — the top predictor of roof damage.
How many homes sit inside the storm's footprint.
Independent storm reports filed with the NWS.
How Alton saw the hail — from two instruments
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
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
1.75"
Detections
0
Radar-estimated hail size
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"
Where May 3, 2026 sits in Alton's hail record
This was Alton's 3rd recorded hail day, arriving 6 days after the Apr 27, 2026 storm. By severity it ranks 2nd of the 4 storms we have logged here. Radar put the day's largest stone over Alton at 1.75" — the largest NEXRAD radar signature.
The May 3, 2026 convective day was bigger than Alton: the same system put hail over 115 other tracked cities, 63 of them in Illinois. Nearest: Bethalto (5 miles east, up to 1"); West Alton (11 miles west, up to 2.5"); Bunker Hill (11 miles northeast, up to 0").
These maps are stills from Alton's May 3, 2026 storm. In the Overview app the same surfaces are live — radar updating in real time, radar-estimated hail size as it forms, and NWS spotter reports pinned where they're filed — with a radar replay you can scrub back over any past day.
What people on the ground reported
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
8 reports Hail size 1.5"
2 NW Alton Madison County
“Report from mPING: Ping Pong Ball (1.50 in.). (LSX)”
— NOAA / SPC storm report
Hail size 1.75"
1 S Godfrey Madison County
“(LSX)”
— NOAA / SPC storm report
Hail size 1.75"
1 NE Alton Madison County
“Report from mPING: Golf Ball (1.75 in.). (LSX)”
— NOAA / SPC storm report
Hail size 1"
Alton Madison County
“(LSX)”
— NOAA / SPC storm report
Hail size 1.5"
1 NNE Bethalto Madison County
“(LSX)”
— NOAA / SPC storm report
Hail size 2"
3 W Alton Madison County
“Email report showing 2 inch stone next to tape measure. time estimated from radar. (LSX)”
— NOAA / SPC storm report
Hail size 1"
3 SW Godfrey Madison County
“Report from mPING: Quarter (1.00 in.). (LSX)”
— NOAA / SPC storm report
Storm forensics
Read from the arrival times and locations of the NOAA ground reports,
not a radar-measured storm track.
How the storm moved
Hail was reported over 11 minutes, from to .
Reports came from Bethalto and Godfrey — beyond Alton itself.
What 1.75" hail means for Alton roofs
At an inch and a half, hail cracks shingles, strips granules down to the mat, and dents gutters, vents, and siding. A footprint like this typically produces a wave of insurance claims — and the contractor who reaches the homeowner first usually gets the inspection.
What this storm is worth to a roofer
$193M
Potential roof exposure — 16,098 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
Illustrative jobs
80 jobs
Illustrative work
~$1.2M
Claims from this storm can typically be filed until around May 2028 — the window to reach these homeowners while it's still open. Deadlines vary by policy and state.
Track hail over Alton on the live map
Radar updates in real time, spotter reports appear on the map as they're filed, and the full Alton storm history — this May 3, 2026 storm included — sits underneath. When you're ready, draw this storm's footprint and pull highly accurate homeowner contact information for every address inside it.
Highly accurate contact information starting at $0.23 per address — every contact included. Digital leads cost $15–$40. Start with a 7-day free trial — no credit card required. See pricing
Alton hail history
← All hail in Alton 4 recorded storm days in Alton, IL
Other storms in Alton
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 surfaces are detections and estimates,
not confirmed damage. Last updated Aug 2, 2026.