Hail in Rock Valley · May 18, 2026
NEXRAD logged 3 hail signatures up to 2"; the estimated-size surface reached 0.5" aloft. At 2" — tennis ball — this is a severe hail signal associated with roof damage. Open it on the live map to see the swath over the streets.
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Convective day · May 18, 2026 · noon–noon UTC
Severity
The 2nd most severe storm Rock Valley 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
- 50 /100
- Homes exposed
- 48 /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 Rock Valley 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.
Radar signature field Where NEXRAD flagged hail as the storm passed — point signatures from the radar, which indicate hail overhead rather than confirm what landed.
Estimated size field 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.
The storm in context
Where May 18, 2026 sits in Rock Valley's hail record.
This was Rock Valley's 2nd recorded hail day, arriving 1 day after the May 17, 2026 storm. By severity it ranks 2nd of the 6 storms we have logged here. Radar put the day's largest stone over Rock Valley at 2" — the largest NEXRAD radar signature.
The May 18, 2026 convective day was bigger than Rock Valley: the same system put hail over 726 other tracked cities, 102 of them in Iowa. Nearest: Hawarden (9 miles southwest, up to 1.75"); Ireton (17 miles south, up to 0.75"); Sheldon (20 miles east, up to 2").
These maps are stills. In the app this date is one of 6 Rock Valley 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.
Nobody on the ground filed a report over Rock Valley for this date, which says more about who was watching than about the storm: spotter reports only exist where there is an observer. The radar surfaces above carry the evidence for this one.
Severe hail signal
What 2" hail means for Rock Valley roofs.
Two-inch-plus hail is capable of puncturing shingles, breaking skylights or windows, and heavily denting soft materials. The strongest radar bands warrant prompt inspection, but neither the signal nor the footprint confirms damage at a specific address.
Radar reading · not confirmed damage
Roofing exposure
What this storm is worth to a roofer.
Potential roof exposure
$3.1M
Potential roof exposure — 258 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
- Illustrative jobs
- 1 job
- Illustrative work
- ~$15K
Close just 0.5% of the 258 homes in this footprint at the average $15,000 roof job. Illustrative math, not a projection — your results depend on your outreach and how the market responds.
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 $54 on top of the $150 plan.
Rock Valley hail history
Other storms in Rock Valley.
Estimated-size surface Jul 4, 2026
1"
Estimated-size surface Jun 30, 2026
1"
Estimated-size surface Jun 29, 2026
1"
Estimated-size surface Jun 27, 2026
4"
Estimated-size surface May 17, 2026
1.75"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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For iPhone. Android coming soon.
Web trial: 7 days free. Card required. $150/month after the trial unless cancelled.