​​​​Coastal High Hazard Area


The County's Comprehensive Plan includes several policies directing actions related to the CHHA. These include policies that prohibit density increases in the CHHA, which were adopted to limit impacts on hurricane evacuation times. At the time these policies were adopted, the CHHA was defined in the Plan as the Category 1 Hurricane Evacuation area. In 2006, the Fl​orida Legislature revised the definition of CHHA to, “the area below the elevation of the category 1 storm surge line as established by a Sea, Lake, and Overland Surges from Hurricanes (SLOSH) computerized storm surge model. (Chapter 163.3178(2)(h), F.S.)

Each affected local government was required to adopt this definition into its Comprehensive Plan, as well as maps depicting the CHHA based on the SLOSH data provided by the State. The State also mandated that Comprehensive Plan amendments that increase density in the CHHA be reviewed for impact on evacuation levels of service, and that the amendments be found in compliance if the local government's adopted (or default State-prescribed) evacuation level of service (LOS) was not exceeded, or if appropriate mitigation was provided for the impact on the LOS.

While this amendment review provision was not relevant for Palm Beach County due to the existing prohibition on density increases including amendments, the change in definition created implementation challenges. Specifically, the irregular boundaries associated with an elevation-based definition, coupled with mapping limitations, has complicated the process of determining what properties, or portions of properties, should be considered to be in the CHHA. This PPM is intended to establish a consistent procedure for these determinations and the subsequent application of the County's CHHA density policies.


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