Tornado Rating unknown
5 WSW Royal Clay County
“Social media video relayed by emergency manager of brief tornado. Location estimated. (FSD)”
— NOAA / SPC storm report
/ Storm field report · Osceola
Hail in Hartley · May 17, 2026
NEXRAD logged 3 hail signatures up to 1.75"; the estimated-size surface reached 1.5" aloft. Open it on the live map to see the swath over the streets.
A tornado was also reported to the National Weather Service during this storm. The ground reports below show where it was filed.
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Peak hail signal 1.75" ≈ golf ball · the largest NEXRAD radar signature
Homes in the hail footprint 70
Ground reports 1 1 tornado
Radar surfaces 2 NEXRAD + estimated size
Convective day · May 17, 2026 · noon–noon UTC
Severity
The 3rd most severe storm Hartley has seen in the last 12 months
Composite score · 4.1 / 10
Storm severity score
Overview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
4.1 /10
- Peak hail signal
- 44 /100
- Homes exposed
- 37 /100
- Ground truth
- 33 /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 Hartley saw the hail — from two instruments
May 17, 2026 · Hartley, IA
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 Surface resolved
Radar signature field 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
1.75"
Detections
3
Radar-estimated hail size Surface resolved
Estimated size field 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
1.5"
The storm in context
Where May 17, 2026 sits in Hartley's hail record.
This was Hartley's 3rd recorded hail day, arriving 34 days after the Apr 13, 2026 storm. By severity it ranks 3rd of the 14 storms we have logged here. Radar put the day's largest stone over Hartley at 1.75" — the largest NEXRAD radar signature.
The May 17, 2026 convective day was bigger than Hartley: the same system put hail over 894 other tracked cities, 139 of them in Iowa. Nearest: Milford (5 miles east, up to 1.75"); Melvin (10 miles west, up to 1"); Sanborn (12 miles southwest, up to 1.75").
These maps are stills. In the app this date is one of 14 Hartley 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.
Tornado reports
1 reportStorm forensics
How the storm moved
Timing and place names from NOAA ground reports
Read from the arrival times and locations of the NOAA ground reports, not a radar-measured storm track.
Reports came from Royal — beyond Hartley itself.
High damage potential
What 1.75" hail means for Hartley 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.
70 homes × $12,000 avg. claim
Potential roof exposure
$840K
Potential roof exposure — 70 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
Claim window
May 2028
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.
Names and phones for every home in the footprint: at most $15 on top of the $150 plan.
Hartley hail history
Other storms in Hartley.
14 recorded storm days in Hartley, IA
Estimated-size surface Storm date Hartley / IA
Sep 6, 2026
0.75" Estimated 0.75"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Sep 1, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Aug 8, 2026
1.25" Estimated 1.25"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Aug 3, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Jul 4, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Jun 29, 2026
1" Signatures 1" Estimated 0.75"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Jun 27, 2026
2.5" Signatures 2.5" Estimated 1.25"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
May 31, 2026
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
May 25, 2026
1" Signatures 1" Estimated 0.75"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
May 24, 2026
0.5" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
May 18, 2026
2.25" Signatures 2.25" Estimated 0.5"
No ground reports filed Open report →
Estimated-size surface Storm date Hartley / IA
Apr 13, 2026
1.25" Signatures 1.25" Estimated 0.75"
No ground reports filed Open report →
NEXRAD surface Storm date Hartley / IA
Mar 5, 2026
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 7, 2026.