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An entire industry has developed around answering one narrow question: did a specific type of severe weather occur at a specific address on a specific date. Weather verification companies compile radar archives, surface observation data, and storm reports into reports formatted for insurance and legal use, and those reports now appear routinely alongside estimates and inspection notes in hail and wind claims across the Midwest. The demand for this kind of service has grown alongside the volume of severe convective storm claims generally, and the reports are now familiar enough that most adjusters, appraisers, and attorneys working in this area have encountered several formats from several different providers.
The methodology behind these services generally mirrors the broader forensic meteorology process, drawing on NEXRAD radar data processed through hail-size estimation algorithms, station-based wind observations, and archived storm reports, then packaging the output into a report tied to a property’s coordinates and a requested date or date range. Some providers supplement this with proprietary modeling intended to refine estimates between radar grid points or to account for local terrain effects. The reports typically present a probability or estimated range for hail size and wind speed at the property rather than a single certain value, reflecting the underlying uncertainty in the source data. Report formats vary from provider to provider, ranging from a brief summary letter to a lengthy technical document with supporting radar imagery, station data tables, and an explanation of the specific algorithm applied.
Because these reports carry an air of scientific authority, it is worth remembering what they are and are not. They are an analysis of atmospheric data for a location and time window, produced through a defined but still probabilistic methodology. They are not a physical inspection of the property, and they do not confirm that damage exists on a particular structure, only that conditions capable of producing damage were present in the area. Two reports from different providers analyzing the same event can also reach somewhat different conclusions depending on the algorithm and data sources each one relies on.
When a weather verification report becomes part of a formal dispute, the questions typically asked of it mirror those asked of any technical evidence: what data sources were used, what methodology converted that data into a conclusion, and what margin of error or confidence level applies to the result. A provider willing to explain and document that methodology in detail, rather than presenting only a summary finding, generally supports a more useful evaluation of the report than one offered without that context, regardless of who commissioned it.
Adjusters, appraisers, attorneys, and policyholders all encounter these reports, and the most useful way to treat them is as one piece of evidence to be reviewed alongside a physical inspection rather than as a conclusive answer on its own. Reviewing the underlying data sources and methodology behind a given report, rather than accepting its summary conclusion at face value, is a reasonable step for any party evaluating one, and any resulting question of coverage remains separate from the weather analysis itself.
This article is general education about how the appraisal process commonly works. It is not legal advice, and specific procedures can vary by state and policy.
Russ Lis is a working property insurance appraiser and umpire based in Minnesota, serving clients nationwide. Contact Appraisal Resolution.