National Flood Insurance Program (NFIP) Maps

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This post details basic information regarding the maps produced for the National Flood Insurance Program (NFIP).  The passages shown in this post have been extracted from the FEMA 480 publication.  It can be downloaded here:

FEMA 480

The passage below defines the following terms:

  • base floodplain
  • Special Flood Hazard Area (SFHA)
  • Base Flood Elevation (BFE)

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The passage below summarizes the odds of a specific recurrence interval occurring over various time periods.  A common computation that is used to convey flood risk is that a structure located in the SFHA (100-yr floodplain) has a 26% change of being flood over the life of a 30 year mortgage.

The math behind that computation is as follows:

where 100 years is the recurrence interval and 30 years is the desired period of years

The computation above gives a 26% chance of occurrence.

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The table below has been extracted from FEMA 480, and it lists the description of the various flood zones.

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You can search for a flood map of a particular area by going to the website shown below.  This site allows the user to enter an address or latitude and longitude coordinates.

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I have developed additional posts to show some floodplain maps that have been obtained from the above site.  The links to these sites are below:

Swamp Creek - Kenmore, WA

 Goose Creek - Sheridan, WY

 Lakeview Area Affected by Hurricane Katrina - New Orleans, LA

 Buffalo Bayou Area Affected by Hurricane Harvey - Houston, TX



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