What this lookup answers

The tool answers one question: on which dates did weather radar detect hail near a specific Minnesota address, and how large was it estimated to be? Enter an address, pick a search radius, and it returns every radar hail signature within that radius since 2011, with the date, the estimated maximum stone size, and the distance from your address.

The date matters more than most homeowners expect. Minnesota insurance policies commonly cut the window for hail lawsuits to one or two years from the date of loss, so establishing when a storm actually passed over your roof is step one of any late claim. Size matters too: hail of 1" or larger is generally accepted as capable of bruising or cracking asphalt shingles, while smaller stones usually strip granules without breaking the mat.

Where the data comes from

Every result comes from NOAA's Severe Weather Data Inventory (SWDI), the public archive of severe weather signatures from the national NEXRAD radar network. A hail signature is an algorithm's estimate that a storm cell carried hail aloft, in the cloud above a location, with an estimated maximum size. It is not a ground report: nobody measured a stone in a yard. Radar geolocation is accurate to roughly a mile, and hail that forms aloft can melt or drift before it lands.

So read results as strong evidence, not proof. A 1.5" signature over your block means a damaging storm was overhead and your roof deserves photographs and an inspection. It does not by itself establish damage. The reverse also holds: a quiet result does not prove your roof was never hit, especially for storms before 2011.

What the search radius means

The radius (1, 2, or 5 miles) is the circle around your address the search covers. Because radar placement is only accurate to about a mile, a 1-mile search can miss storms that actually passed overhead. Two miles is the sensible default for a house; five miles is useful when you only remember the town, not the block.

Coverage and limitations

The archive covers Minnesota from 2011 to the present and is refreshed as NOAA publishes new signatures. Results reflect what the radar algorithms recorded, nothing more: no ground truth, no roof inspections, no data before 2011. If a recent date shows up over your address, start with the first 48 hours, then check your policy's deadline clause before any contractor paperwork.