Historic information on hurricanes, tornadoes, and other severe wind events comes from publicly available government sources.
Wind Factor reports provide historic information on hurricane events, tornadoes, and severe storm wind events that have occurred in the county where the property is located. It also provides additional information on the most severe event within that county based on wind speed. This information is sourced from freely available government datasets that have varying levels of quality control.
Historic hurricane data was sourced from the NOAA National Hurricane Center Atlantic hurricane database best track data (HURDAT2) (NOAA, n.d.). HURDAT2 data. It includes 6-hourly data on the location, maximum winds, and central pressure of historic cyclone events from 1851-2021. The size of historic cyclones, including radii for 34, 50, and 60-knot winds and the radius of maximum winds, are provided from 2004-2021. For events prior to 2004, we assume the size of the cyclone based on the Saffir-Simpson scale and the average radii across similar category storms in the post-2004 events to determine counties that were likely affected by the storm path. For post-2004 events, The provided radii extents in the northeastern, southeastern, southwestern, and northwestern directions were used to create a buffer around each measurement, which was then interpolated to create continuous regions of maximum wind for each storm track. We apply the gust-conversion factor (1.28) derived for the hurricane wind model to estimate the 3-second gusts associated with each historical storm. These gust estimates are approximations based on coarse data and may vary from observed gusts recorded at specific locations.
Historic tornado information was sourced from the NOAA Storm Prediction Center’s Severe Weather Database (NOAA, 2022). Individual tornado entries exist from 1950 through 2021. The tornado information includes the intensity of each event, which is measured on the Fujita Scale until 2007 and the Enhanced Fujita Scale after 2007, as well as information on injuries, fatalities, and economic losses in U.S. dollars. We define ‘affected counties’ with summary statistics including storm count, injuries, fatalities, and losses.
Other severe wind
Other severe wind data (mostly thunderstorms) were also sourced from the Severe Weather Database (NOAA, 2022). Wind events are represented in the database from 1955 through 2021. The majority of reports are verified by falling trees or damage to buildings, not by observed wind gusts. This means that there is a possible bias towards areas with trees or higher population density. Individual entries for events in the database can include multiple reports of damage or injury for a particular weather event, so data points are aggregated both by geography (county) and temporal proximity. A series of events within a county where an event occurred within three hours of the next event is considered a cluster. Wind event intensities are reported as maximum wind speed (where available) instead of a categorization.