Executive Summary

The Nassau County Hazard Mitigation Plan (Plan) is tangible evidence of Nassau County’s dedication to identifying and reducing the risks associated with natural hazards to increase resilience of the community. Additionally, the County recognizes the importance of maintaining a Federal Emergency Management Agency (FEMA) approved hazard mitigation plan in order to maintain eligibility for the FEMA Hazard Mitigation Assistance (HMA) program, thereby opening the door to additional financial resources for the County.

Planning Process

Nassau County, in coordination with stakeholder groups, conducted a comprehensive, year-long planning process to update and redevelop their hazard mitigation plan to account for new risk data and cater to updated community priorities. Through this process, the County established a group of jurisdictions interested in participating (i.e., Planning Committee), identified hazards of concern, profiled these hazards, estimated risk and potential losses associated with these hazards, developed mitigation goals and actions that address the hazards that impact the area, and developed a strategy for plan implementation, to be executed upon conditional approval of the plan from the New York State Division of Homeland Security and Emergency Services (NYS DHSES) and FEMA. 

Risk Assessment

The purpose of the risk assessment is to evaluate the risks of natural hazards that are anticipated to impact the people, economy, services, housing, infrastructure, and environment of Nassau County. This assessment evaluated coastal hazards, drought, extreme temperatures, flooding, ground failure hazards, hail, hurricanes and tropical storms, lightning, severe winter weather, and straight line winds. Key considerations in this analysis were the likelihood that a hazard would occur (probability of occurrence), the anticipated severity (extent) of the hazard, and anticipated impact of the hazard on the community. The assessment found that:

Highly Likely

A hazard that occurs one or more times every year  


A hazard that occurs at least once every five years


A hazard that occurs less than every five years  

  • Coastal Hazards
  • Flooding
  • Severe winter weather
  • Straight-line winds
  • Drought
  • Extreme temperatures
  • Hail
  • Hurricanes and tropical storms
  • Lightning
  • Ground failure hazards
  • Tornadoes


Mitigation Strategy

The mitigation strategy is the heart of the Nassau County Hazard Mitigation Plan. This section defines the County’s vision for mitigating risk and reaching resilience. The section details an implementation strategy that will be carried out over the next five years. The cornerstone of the County’s Mitigation Strategy are these six mitigation goals that all mitigation actions align with:

  • Goal 1: Build stronger by promoting mitigation actions that emphasize sustainable construction and design measures to reduce or eliminate the impacts of natural hazards now and in the future.
  • Goal 2: Build and support local capacity to prepare for, respond to, and recover from disasters.
  • Goal 3: Protect existing property including public, historic, private structures, state-owned/operated buildings, and critical facilities and infrastructure.
  • Goal 4: Increase awareness of hazard risk and mitigation capabilities among stakeholders, citizens, elected officials, and property owners to enable the successful implementation of mitigation strategies.
  • Goal 5: Develop and implement long-term, cost effective, and resilient mitigation projects to preserve or restore the functions of natural systems.
  • Goal 6: Improve coordination between land use and redevelopment planning to encourage safe, economically sound investments.


Plan Organization

This Plan consists of the Base Plan, its Appendices, and the Jurisdictional Annexes. The Base Plan is comprised of the following sections:

  • Section 1 Introduction introduces the reader to the Plan and provides context for the information included in the Plan.
  • Section 2 Planning Process describes the planning process and records participation of various stakeholders in the planning process.
  • Section 3 County Profile analyzes the current and future demographics, geography, and climate in the County to inform the mitigation planning process.
  • Section 4 Risk Assessment analyzes the County and its jurisdictions’ risk and vulnerabilities to natural hazards.
  • Section 5 Capability Assessment collates the County’s capabilities and assesses how these capabilities can support mitigation programs or be improved to support mitigation.
  • Section 6 Mitigation Strategy describes the County’s mitigation strategy, including the Plan’s goals for a mitigation program, Countywide mitigation actions, and a road map for how the County will implement the Plan throughout the five year planning cycle.

The Base Plan Appendices include tools and data that supported the development of the plan or will support the implementation of the plan. Lastly, each participating jurisdiction has its own Jurisdictional Annex that details a jurisdiction-specific profile, capability assessment, and mitigation strategy.