# Method and sources

HomeRiskIQ calculated distinct 2025 county event-start dates from NOAA Storm Events details, revision 20260819. The current NOAA directory and a fresh download were checked October 30, 2026. The input checksum and source URLs are recorded in the accompanying public source manifest.

Select county-coded records (`CZ_TYPE=C`) for the exact county FIPS below, then include hail of at least 1 inch or Thunderstorm Wind of at least 50 knots with `MAGNITUDE_TYPE=MG`. MG means NOAA coded the gust as measured; it is not an independent calibration or completeness guarantee. Hail sizes may be estimated or measured. Group the date portion of `BEGIN_DATE_TIME` within county. Counts are source-local event-start dates, not independent storms, all dates touched, report-submission dates, damage counts or property exposure.

Higher-threshold sensitivity uses hail >=1.5 inches OR MG wind >=60 knots. Source sensitivity keeps all qualifying hail but restricts MG wind to exact SOURCE categories ASOS, AWOS and Official NWS Observations. Neither produces complete or equivalent station coverage. Inventories of source/location labels are not station counts. No matched-station baseline or continuity study is supplied. Event location names are reference localities, not full footprints; use range/bearing and coordinates in raw rows for geographic inspection.

The selected records have no duplicated EVENT_ID, no start-date/component mismatch, no cross-midnight rows and no 23-hour starts. Adding one hour leaves all selected date sets unchanged; the published metric remains the source-local start date.

Missing reports are not evidence that a hazard did not occur. Damage-only/estimated-wind-only records, smaller events and other weather categories are excluded. Counties differ in geography, stations and reporting practices. These one-year descriptions do not establish climate trends, future loss probabilities, property risk, repair delays or insurance outcomes.

Data: https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/StormEvents_details-ftp_v1.0_d2025_c20260819.csv.gz

Definitions: https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/Storm-Data-Bulk-csv-Format.pdf

Reproduction: place the raw download beside `analyze.py` with the name `noaa_2025_fresh.csv.gz`, then run `python analyze.py` with pandas and matplotlib installed. The script writes both analyses and their charts. CSVs contain the exact selected records, date presence, monthly counts and source/location inventories. Calculations JSON contains primary, higher-threshold, source-restricted and narrative-conflict-exclusion date sets.

## County scope

Pennington SD FIPS 46103; Meade SD FIPS 46093.

## Narrative consistency

Three Meade MG-coded wind entries on August 13 (1292731,1292733,1292735) have short narratives saying estimated. Pennington hail entry 1285612 has a wind-related narrative. Omitting these rows leaves the primary date and hazard-overlap classifications unchanged because other qualifying records remain on those dates. Preserve this distinction between coded data and independent instrument verification. A July 10 Pennington wind narrative mentions a heat burst; NOAA event classification is preserved.