About
Severe Convective Storms
Hail
Hail on Peril Report uses FEMA’s National Risk Index for the county. The headline is the expected annual loss rating (for example, Relatively Low), not the composite hail risk rating that also folds in social vulnerability and community resilience.
The percentile bar is the expected annual loss rate compared with other U.S. counties. The text also reports how often hail occurs in the NRI record and prorates historic and modeled building-loss ratios over 100 years.
Tornadoes
Tornado chances use Storm Prediction Center tornado tracks from 1950 through 2017. Peril Report counts tracks that intersect the Census county containing the address, for any tornado (EF0 or above) and for strong tornadoes (EF3 or above). The annual chance is a Poisson estimate from that county history: 1 − exp(−count / years). The rating in the section is FEMA’s National Risk Index tornado expected annual loss rating, which is separate from those track-based chances. The percentile bar is the tornado expected annual loss rate compared with other U.S. counties. The text also prorates historic and modeled building-loss ratios over 100 years.
| Category | Wind speeds | Expected damage |
|---|---|---|
| EF0 | 65–85 mph | Light. Broken branches, damaged chimneys, some roof shingles peeled. |
| EF1 | 86–110 mph | Moderate. Roofs stripped, windows broken, mobile homes shifted or overturned. |
| EF2 | 111–135 mph | Considerable. Roofs torn off frame houses, large trees snapped, cars lifted. |
| EF3 | 136–165 mph | Severe. Entire stories of well-built houses destroyed, trains overturned, heavy cars thrown. |
| EF4 | 166–200 mph | Devastating. Well-constructed houses leveled, cars thrown large distances. |
| EF5 | Over 200 mph | Incredible. Well-built houses swept from foundations, steel-reinforced structures badly damaged. |
Wind
Wind uses NOAA NCEI’s Global Hourly Integrated Surface Database. Peril Report finds the nearest land weather station to the address, then reports the highest daily maximum wind in that station’s record (including earlier NCEI identifiers for the same site). Gusts are used when NCEI publishes them; otherwise the figure is the highest daily maximum sustained wind. Speeds are shown in miles per hour, with the station name, distance from the address, and the date of the peak.