Reports - Mississippi Renewal

THE GOVERNOR’S COMMISSION REPORT | 53pre-Katrina Flood Insurance Rate Map(FIRM) designations are helpful inconsidering this issue. Areas within theFIRM are deemed prone to flooding,and thus households within the FIRMwere more likely to have had flood insurancethan those in other areas. Theother option for evaluating damageexposure is from the Surge InundationLimits (SIL). The SIL data were modeledby FEMA based upon field measuresof post-Katrina High Water Marks(HWM) and recent Light Detectingand Ranging (LIDAR) surveys. Table2, shown previously, provides estimateson the number of housing units withineither SIL or FIRM bounded areas;these represent a rough estimate on thenumber of housing units exposed to eithersurge or flooding conditions in thethree coastal county area.As shown in Table 2, more than40,000 housing units across the threecountyarea fell within the FIRM area,and, therefore, faced a higher likelihoodof damage from flooding. In these samethree counties, more than 75,000 housingunits were within the SIL area andfaced potential damage from stormsurge. What these numbers indicate isthat between 25 and 50 percent of allhousing units in the three-county areafaced likely damage by flooding, bystorm surge, or by both. These roughestimates, however, almost are certainlylower than the actual number of homesdamaged or destroyed. First, the calculationsdo not consider wind damage,which could occur in areas not affectedby flooding or storm surge. Second, thehousing numbers are now five years oldand do not include new homes built inthe region since 2000.Tying together the questions of demographicsand damages across thethree counties, the data in Table 2 showTable 2: Three-County Housing Assessment.Figure 5: Surge inundation limit and 100-year fl ood extent overlay onpercent of housing units built before 1980 in coastal areas.