Impact Frequency

The Impact Frequency is calculated for landfalling Tropical Systems (TS, H1,H2,H3,H4,H5) based on 6 Hourly warnings, as well as those systems that move from another county, through the county of interest and then into another county or move from the county of interest to offshore. The systems that come ashore in a nearby county and affects the county of interest but the eye does not enter the county are ignored. (this is partially due to the lack of wind radius on earlier systems.

The Direct Impact Frequency "1 / 5" indicates that statistically one year will have a Direct Impact and then 4 years will pass without another Direct Impact in that county. The Impact Frequency "1 in 23" under El Nino indicates that one El Nino year will have a Direct Impact and then 22 El Nino Years will pass without another Direct Impact in that county.

The Return Frequency "1 / 0" indicates that no Direct Impacts was recorded for that county since 1851 during that particular ENSO Phase.

The years are colored based on ENSO Phase. Red is El Nino or the Warm Phase, Green is the Neutral Phase and Blue is La Nina or Cold Phase.

The following symbols apply: 1 is a Category One Storm that move on-shore into the county or a landfalling system. (1) is a Category One Storm that moves from an another county into the county of interest and then out through a third county. [1] is a Category One Storm that moves from an another county into the county of interest and then moved off-shore over the coastline of the county of interest.

Cat

Category

Wind Speed

Damage Estimates and Storm Examples

No real damage to buildings. Damage to unanchored mobile homes. Some damage to poorly constructed signs. Also, some coastal flooding and minor pier damage.

Some damage to building roofs, doors and windows. Considerable damage to mobile homes. Flooding damages piers and small craft in unprotected moorings may break their moorings. Some trees blown down.

Some structural damage to small residences and utility buildings. Large trees blown down. Mobile homes and poorly built signs destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain may be flooded well inland.

More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Terrain may be flooded well inland.

Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required.