NEXRAD logged 0 hail signatures up to 1"; the estimated-size surface reached 0.5" 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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Convective day · Apr 17, 2026 · noon–noon UTC
Severity
Overview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
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
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
This was Union Grove's 3rd recorded hail day, arriving 18 days after the Mar 30, 2026 storm. By severity it ranks 2nd of the 5 storms we have logged here. Radar put the day's largest stone over Union Grove at 1" — the largest NEXRAD radar signature.
The Apr 17, 2026 convective day was bigger than Union Grove: the same system put hail over 1,016 other tracked cities, 178 of them in Wisconsin. Nearest: Franksville (6 miles northeast, up to 1"); Muskego (11 miles north, up to 1"); Franklin (11 miles north, up to 1").
These maps are stills. In the app this date is one of 5 Union Grove 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
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.
“NWS Damage Survey reported EF-1 Tornado... estimated peak winds of 100 mph. Began on west side of US-45 in northern Racine Co and tracked northeast to County Line Rd on (MKX)”
— NOAA / SPC storm report
“NWS Damage Survey reported EF-0 Tornado... estimated peak winds of 80 mph. Began on west side of US-45 in northern Racine Co near North Cape and tracked northeast to 7 (MKX)”
— NOAA / SPC storm report
“NWS Damage Survey concludes an EF-0 tornado occurred with estimated peak winds of 70 mph and a width of 75 yards. The tornado started near the intersection of Kelsey Dr (MKX)”
— NOAA / SPC storm report
Storm forensics
Read from the arrival times and locations of the NOAA ground reports, not a radar-measured storm track.
Reports came from Wind Lake — beyond Union Grove itself.
Damage-capable hail signal
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
Roofing exposure
Potential roof exposure
$47M
Potential roof exposure — 3,958 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.
Close just 0.5% of the 3,958 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
April 2028
Claims from this storm can typically be filed until around April 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 $831 on top of the $150 plan.
Union Grove hail history
Estimated-size surface 
Estimated-size surface 
Estimated-size surface 
Estimated-size surface Set your territory and alerts today. When hail hits, use Overview to choose your streets and get moving.
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Web trial: 7 days free. Card required. $150/month after the trial unless cancelled.