LMS Mapping Data Sets Methodology Quick Reference

 

Hurricanes/Winter Storms

            Historical storms (past 153 years for tropical cyclones and past 50 years for winter storms) were simulated using the TAOS model, version 10.2.  Winds, wave, rainfall, and storm surge perils were computed, and hazard zones created.  Flood zones and wind layers were created, and tables were created based on percent damage expected.  Additionally, FEMA Flood Insurance Rate Map (FIRM) data was ingested, and the tabular data sets were run for comparison.

 

Tornadoes

            Tornado track data since 1950 from the National Weather Service was analyzed to determine the annual probability that a tornado would cause damage to a structure in each 90m grid cell in Florida.  The data was stratified into four annual probability classes:  High risk (1 in 100 or greater), Medium risk (1 in 101 to 1 in 250), or low (1 in 250 to 1 in 500 chance). 

 

Tsunami

            Tsunami risk in Florida is difficult to assess, as there are minimal reliable historical records. Consequently, simulation techniques were used. Three classes of initiating events were simulated:  Caribbean volcanic events, Caribbean and Central American earthquakes, and East Atlantic (Azores) volcanic events.  In general, in north Florida, these events produced at worst a 4 meter wave, while in some parts of south Florida this value grew to nearly 6 meters.  Expert Opinion suggests that this would be approximately a 1 in 500 year event.  Note that these tsunami zones are all smaller than those of a category 5 hurricane, which is probably an event of comparable frequency.  However, a tsunami wave from the Azores would more than likely inundate virtually all of the Atlantic coastline, as opposed to only a few dozen miles of coastline in the case of a hurricane.

 

Wildfire Potential

            The wildfire potential map was created by reclassifying the land cover data sets created for the hydrologic models.  These data sets were reclassified to equate the Anderson Level II classification to fuel models used in the National Fire Danger Rating System (Burgan et al, 2000). These fuel models are an indication of the ability of a fire to start and spread in the given terrain type, and are used as the input to the Fire Potential Index as well as fire spreading models.  The resulting map was compared with the NFDR Fuel Model Map created by the US Forest Service (USFS).  The NFDR Fuel Model Map is used for the next generation fire danger rating system being developed by USFS, and is a nationwide map at a resolution of 1000 meters per grid cell based on data from 1997.  The KAC developed map for Florida is at a resolution of 90 meters, and compares well the much more general national map while providing a great deal of additional detail, as well as being more up to date due to land cover changes.

 

 Each of the fuel models was assigned to a risk code of “low”, “medium”, or “high”, based on fire spreading potential during a climatologically “dry” year, and processed with the statewide parcel data base to create the tables supplied with the LMS analysis. The mode of the fuel types within 500 meters of the parcel was used to determine risk category for the parcel.

 

Sinkhole Potential

            Sinkhole potential was determined according to points assigned to each 90m grid cell in the state.  Three classes of points were assigned, for distance to historic sinkholes, geology, and soils:

 

2 points if cell was within 2000m of an existing sinkhole;

1 point if cell between 2000m and 5000m of an existing sinkhole;

1 point if the cell was in the same USGS surface geologic unit as an existing sinkhole;

1 point if the cell was in the same NRCS soil unit as an existing sinkhole.

 

Thus, each cell as assigned a value from 0 to 4:

            0: no significant risk

            1: low risk

            2: moderate risk

            3: high risk

            4 very high risk.

 

 

Earthquake Risk

            The USGS 50 year 10% likelihood data set was used to assign earthquake risk.  The peak ground acceleration (PGS) value was used to create four zones:

 

            < 0.01g           Almost none

            0.01g              Minimal  (0.01, 0.02)

            0.02g              Very low  (0.02, 0.03)

            0.03g              Low  (0.03, and higher

 

Note that the earthquake risk, even in the “highest” risk zone in the state, is quite small.

 

Exposure Data Base

            The 2000 Department of Revenue Tax Records and Census 2000 data sets were used to create the structure inventory data base.  First, the DOR records were address matched against the TIGER Road files.  This resulted in positions for approximately 70% of the records statewide.  The remaining records were either partial matched (15%), matched to the zip code (5%), or to the nearest TRS point (10%).

 

Back to the index.