How our pages are built

• NOAA Storm Events database, since 2015, 2026 to date included: county-level hail of one inch or more, thunderstorm wind of 65 knots or more and tornadoes; it supplies the storm counts, the largest hail size and the most recent hail date.
• NOAA Storm Prediction Center point reports, 2000 to 2024: hail reports within 15 km of each town, the peak month and the hail season.
• FEMA National Risk Index and OpenFEMA: hail, hurricane and winter-storm risk ratings for the county and the count of federal weather disaster declarations from 1965 to date.
• U.S. Census Bureau American Community Survey 2019 to 2023 five-year estimates: housing units, share built before 1980, median year built and owner occupancy. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
• NCEI 1991 to 2020 climate normals from the nearest station: freezing days, snowfall, precipitation and days at 90 F or above.
• Census County Business Patterns 2022: the number of roofing businesses in the county.
• EIA Residential Energy Consumption Survey 2020: the share of homes with asphalt shingle and metal roofs by state.
• State licensing boards and local permit registries: the licensing rule, the lookup link and permit notes.
• GeoNames (CC BY 4.0): place names and coordinates.

Our software joins these datasets to each metro area and town, then fills the data tiles, the map, the storm log and the sentences that quote a number. Short explanatory passages are drafted with software assistance from the same facts and checked so that every number on the page exists in the source data. A person reviews the templates, the sources and a sample of every batch of pages before publication, and the editorial policy names who is responsible.

Every page carries facts for its own place, with the source and the year next to each one, and a section that would carry only general advice with no place-specific fact is not published. Two towns in the same county share the county's storm count, but each town page shows its own housing figures and its own hail reports within 15 km, so the pages differ because the places differ. No page is published below its word floor, and a page that shares too much text with a sibling page is held out of the search index until it is rewritten.

Every location page ends with a small sources line naming the datasets used on that page: NOAA Storm Events and SPC, the FEMA National Risk Index, U.S. Census ACS 2019 to 2023 and the state licensing board, followed by the month the data was last updated. A number that is not in one of the named sources is an error; report it.

Storm counts are county-level, so two towns in one county share the same count. ACS estimates carry margins of error, and medians in the lowest interval are shown as "1939 or earlier". Climate normals come from the nearest station, which can be some miles away in rural counties. Data vintages are printed on every data panel.

Email hello@roofershotline.com with the page address and what is wrong. Corrections are made at the next build.