Revised Flood Insurance Rate Maps Published

At the invitation of Mayor Ron Ciancio, Charleston County officials conducted an open house on Seabrook to give residents an opportunity to learn about revised Flood Insurance Rate Maps (FIRMs) published recently by FEMA and to see the maps’ implications for their properties. (Instructions for accessing this data are provided below.)

Carl Simmons, Director of Building Inspection Services for Charleston County, briefly explained what is changing.  The maps that are currently in effect are based on survey information from 1929 that was updated in 1988.  Coastal Flood Hazard Zones depicted on these FIRMs are Zone VE (where the flood elevation includes wave heights equal to or greater than 3 feet) and Zone AE (where the flood elevation includes wave heights less than 3 feet).

The revised FIRMs, considered to be “preliminary” until completion of a review and comment period, are far more accurate because they were developed using modern Light Detection and Ranging (LiDAR) technology.  These maps depict a new concept called “LiMWA,” a curvy line superimposed on the map’s designations of AE flood zones to indicate “Limit of Moderate Wave Action.”  According to FEMA, “The addition of the LiMWA area to FIRMs allows communities and individuals to better understand the flood risks to their property.  The LiMWA area alerts property owners on the seaward side of the line that although their property is in Zone AE, their property may be affected by 1.5-foot or higher breaking waves and may therefore be at significant risk during a 1-percent-annual-chance flood event.”  For a more complete explanation of the importance of LiMWA, click here to see FEMA’s Fact Sheet on the subject.

Mr. Simmons emphasized that LiMWA and the related definition of a new “Coastal A Zone” between Zones AE and VE are not part of the National Flood Insurance Program (NFIP) regulations at this time.  However, they are under consideration by Congress.  He added that the information provided by the LiMWA designation should be useful to individuals and communities as they plan structural elements for homes located in AE zones—perhaps some should be constructed with consideration for requirements that are currently in place for VE zones.

This open house and others countywide were held to arm property owners with information and resources to determine whether there is reason to dispute the new elevation designations for their properties.  Mr. Simmons said that most properties on Seabrook Island, unlike some other areas of Charleston County, actually benefit from an elevation change of about one foot.

According to Mr. Simmons, the timing of events that will occur before “preliminary” FIRMs are finalized and become the basis for flood insurance rates is likely to be:

  • A 90-day period for formal review and comment will not begin until the preliminary FIRMs are filed in the Federal Register.
  • June 2018 is the estimated date for publishing Letters of Final Determination.
  • December 2018 is the estimated date for distribution of FIRMS that have final FEMA approval to jurisdictions (e.g., local governments).
  • Local governments (such as the Town of Seabrook Island) will have 6 months to formally adopt the new FIRMs.

Mr. Simmons indicated that it is ulikely the FIRMs will be in final form for the Town’s adoption before 2019.

For instructions on how to access FEMA Flood Map information on the Charleston County website, click here.

To see Frequently Asked Questions Regarding Flood Map Updates, click here.

Tidelines Editors










[Cathrine:  Make the two items below into hot links to the handouts?]

  • Finding FEMA Flood Map Information on the Charleston County website
  • Frequently Asked Questions Regarding Flood Map Updates


Mr. Simmons encouraged property owners with questions or concerns to contact his


Tidelines Editors

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