Hail size 1"
4 NNW Swaledale Cerro Gordo County
“on I35 near mile marker 186. time estimated from radar. (DMX)”
— NOAA / SPC storm report
Hail in Mason City May 15, 2026
Both radar surfaces caught this storm: NEXRAD logged 0 hail signatures up to 2.5", and the radar-estimated size reached 2" aloft. At 2.5" — baseball — this is severe, roof-replacing hail: close to every roof inside the footprint becomes a claim candidate.
Largest hailstone
2.5"
≈ baseball · the largest NEXRAD radar signature Homes in the hail footprint
4,449
Ground reports
1
1 hailThe most severe storm Mason City 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.
5.8 /10
- Hail size
- 63 /100
- Homes exposed
- 73 /100
- Ground truth
- 17 /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 Mason City saw the hail — from two instruments
The maps here read the same storm from two angles — point detections from NEXRAD, and modeled hail size aloft. Where the two disagree is informative: it marks where estimated size outran the signatures, or trailed them.
NEXRAD radar signatures
Where NEXRAD flagged hail as the storm passed — point signatures from the radar, which indicate hail overhead rather than confirm what landed.
Max size
2.5"
Detections
0
Radar-estimated hail size
The modeled maximum hail size across the swath, derived from radar aloft — the largest stone the storm could have supported, which is not necessarily what reached the ground.
Max size
2"
Where May 15, 2026 sits in Mason City's hail record
This was Mason City's 3rd recorded hail day, arriving 32 days after the Apr 13, 2026 storm. By severity it ranks 1st of the 9 storms we have logged here. Radar put the day's largest stone over Mason City at 2.5" — the largest NEXRAD radar signature.
The May 15, 2026 convective day was bigger than Mason City: the same system put hail over 444 other tracked cities, 236 of them in Iowa. Nearest: Clear Lake (8 miles southwest, up to 2.5"); Swaledale (11 miles south, up to 2.5"); Rockford (12 miles southeast, up to 1.75").
These maps are stills from Mason City's May 15, 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
1 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
Reports came from Swaledale — beyond Mason City itself.
What 2.5" hail means for Mason City roofs
Two-inch-plus hail punctures shingles, breaks skylights and windows, and dents anything soft. In the core of a footprint like this, close to every roof is a candidate for an insurance claim. Speed decides who writes those jobs.
What this storm is worth to a roofer
$53M
Potential roof exposure — 4,449 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
Illustrative jobs
22 jobs
Illustrative work
~$330K
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 Mason City on the live map
Radar updates in real time, spotter reports appear on the map as they're filed, and the full Mason City storm history — this May 15, 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
Mason City hail history
← All hail in Mason City 9 recorded storm days in Mason City, IA
Other storms in Mason City
Jul 20, 2026
1.25" Estimated 1.25"
No ground reports filed 
Jul 8, 2026
1.75" Signatures 1.75" Estimated 1"
No ground reports filed 
Jul 2, 2026
2.5" Signatures 2.5" Estimated 1.75"
No ground reports filed 
Jul 1, 2026
1.25" Signatures 1" Estimated 1.25"
No ground reports filed 
Jun 28, 2026
1" Signatures 1" Estimated 0.5"
No ground reports filed 
May 17, 2026
Apr 13, 2026
0.75" Estimated 0.75"
No ground reports filed 
Apr 11, 2026
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 3, 2026.