Both radar surfaces caught this storm: NEXRAD logged 0 hail signatures up to 1", and the radar-estimated size reached 0.5" aloft.
A tornado was also reported to the National Weather Service during this storm — see the ground reports below.
1"
≈ quarter · the largest NEXRAD radar signature3,958
3
3 tornadoOverview's storm severity score weighs hailstone size, homes in the footprint, and ground-truth reports.
Largest hailstone — the top predictor of roof damage.
How many homes sit inside the storm's footprint.
Independent storm reports filed with the NWS.
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.
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.
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.
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"); Waterford (11 miles west, up to 1.75"); Muskego (11 miles north, up to 1").
These maps are stills from Union Grove's Apr 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.
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
Reports came from Wind Lake — beyond Union Grove itself.
Quarter-size and larger hail is where asphalt shingle damage starts in earnest: bruised mats and granule loss that homeowners can't see from the ground. Most people inside the footprint won't know their roof was hit until someone inspects it.
$47M
Potential roof exposure — 3,958 homes × the ~$12,000 industry-average hail roof claim. Exposure, not confirmed damage.Radar updates in real time, spotter reports appear on the map as they're filed, and the full Union Grove storm history — this Apr 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
5 recorded storm days in Union Grove, WI
