Tornado Rating unknown
3 SSW Armstrong Emmet County
“Confirmed tornado estimated via webcam. (DMX)”
— NOAA / SPC storm report
Hail in Armstrong May 17, 2026
Both radar surfaces caught this storm: NEXRAD logged 0 hail signatures up to 0", and the radar-estimated size reached 0" aloft.
A tornado was also reported to the National Weather Service during this storm — see the ground reports below.
Largest hailstone
0"
≈ pea to penny · radar-estimated size aloft Homes in the hail footprint
0
Ground reports
1
1 tornadoThe 11th most severe storm Armstrong 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.
0.5 /10
- Hail size
- 0 /100
- Homes exposed
- 0 /100
- Ground truth
- 33 /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 Armstrong saw the hail — from two instruments
We map this storm two ways: the NEXRAD radar signatures the storm produced overhead, and the radar-estimated size of the hail in the air. The two surfaces don’t have to match — where they diverge is where estimated size aloft ran ahead of, or behind, what the signatures caught.
NEXRAD radar signatures
NEXRAD radar signatures — the point detections the storm produced overhead. A signature is where the radar saw hail, not a confirmed stone on the ground.
Max size
0"
Detections
0
Radar-estimated hail size
Maximum hail size as estimated from radar aloft. Treat it as the storm's ceiling — the largest supportable stone — rather than a ground measurement.
Max size
0"
Where May 17, 2026 sits in Armstrong's hail record
This was Armstrong's 4th recorded hail day, arriving 2 days after the May 15, 2026 storm. By severity it ranks 11th of the 11 storms we have logged here. Radar put the day's largest stone over Armstrong at 0" — radar-estimated size aloft.
The May 17, 2026 convective day was bigger than Armstrong: the same system put hail over 894 other tracked cities, 139 of them in Iowa. Nearest: Welcome (9 miles northwest, up to 1.75"); Sherburn (12 miles northwest, up to 1.75"); Swea City (12 miles southeast, up to 1").
These maps are stills from Armstrong's May 17, 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.
Tornado reports
1 reportWhat 0" hail means for Armstrong roofs
Hail under three-quarters of an inch stays below the National Weather Service severe threshold and rarely breaks shingles outright. But repeated small-hail events accelerate granule loss and shorten roof life — on older roofs, it's still worth a conversation.
Track hail over Armstrong on the live map
Radar updates in real time, spotter reports appear on the map as they're filed, and the full Armstrong storm history — this May 17, 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
Armstrong hail history
← All hail in Armstrong 11 recorded storm days in Armstrong, IA
Other storms in Armstrong
Jul 4, 2026
1" Signatures 1"
No ground reports filed 
Jun 30, 2026
1" Signatures 1"
No ground reports filed 
Jun 29, 2026
1" Signatures 1" Estimated 0.5"
No ground reports filed 
Jun 1, 2026
1.25" Signatures 1.25" Estimated 1"
No ground reports filed 
May 26, 2026
1" Signatures 1" Estimated 0.5"
No ground reports filed 
May 25, 2026
1" Signatures 1" Estimated 0.5"
No ground reports filed 
May 18, 2026
1" Signatures 1" Estimated 0.5"
No ground reports filed 
May 15, 2026
2" Signatures 2" Estimated 1.25"
1
ground report 
May 14, 2026
0.75" Signatures 0.75"
No ground reports filed 
Apr 13, 2026
2.25" Signatures 2.25" Estimated 1.5"
No ground reports filed
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.