Hail in Decorah · May 15, 2026
NEXRAD logged 0 hail signatures up to 1"; the estimated-size surface reached 0" aloft. Open it on the live map to see the swath over the streets.
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Convective day · May 15, 2026 · noon–noon UTC
Severity
The 8th most severe storm Decorah has seen in the last 12 months
Overview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
- Peak hail signal
- 25 /100
- Homes exposed
- 0 /100
- Ground truth
- 0 /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 Decorah 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.
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.
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.
The storm in context
Where May 15, 2026 sits in Decorah's hail record.
This was Decorah's 4th recorded hail day, arriving 18 days after the Apr 27, 2026 storm. By severity it ranks 8th of the 11 storms we have logged here. Radar put the day's largest stone over Decorah at 1" — the largest NEXRAD radar signature.
The May 15, 2026 convective day was bigger than Decorah: the same system put hail over 444 other tracked cities, 236 of them in Iowa. Nearest: Calmar (10 miles southwest, up to 0"); Ossian (14 miles south, up to 1"); Elgin (29 miles south, up to 0").
These maps are stills. In the app this date is one of 11 Decorah 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
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.
No ground reports were filed with the National Weather Service for this storm over Decorah. That is common: a report depends on someone being there to see it and take the time to call it in. The radar surfaces above are the record here — the storm was detected from above even though no one on the ground logged it.
Damage-capable hail signal
What 1" hail means for Decorah roofs.
Quarter-size and larger hail can bruise asphalt mats, remove granules, and dent exposed soft metal. The mapped footprint identifies an inspection priority area — it does not identify which individual roofs, if any, sustained damage.
Radar reading · not confirmed damage
Decorah hail history
Other storms in Decorah.
Estimated-size surface Sep 4, 2026
1.25"
Estimated-size surface Aug 11, 2026
0.75"
Estimated-size surface Jul 16, 2026
0.5"
Estimated-size surface Jul 2, 2026
1.75"
Estimated-size surface Jul 1, 2026
2.5"
Estimated-size surface Jun 10, 2026
0.5"
Estimated-size surface Jun 5, 2026
1.75"
Estimated-size surface Apr 27, 2026
1"
Estimated-size surface Apr 23, 2026
Estimated-size surface Apr 17, 2026
0.75"The next storm won’t wait for you.
Set your territory and alerts today. When hail hits, use Overview to choose your streets and get moving.
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