Nassau County Disaster Risk

Nassau County has a FEMA National Risk Index rating of Relatively High, placing it in the 97th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.

Nassau County is evaluated for five major natural hazard types: flooding (98th percentile), earthquake (96th percentile), hurricane (95th percentile), tornado (76th percentile), wildfire (44th percentile). The highest-risk hazard is flooding at the 98th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.

Nassau County's composite risk percentile is 97th, compared to the New York state average of 69th percentile. The state's overall risk rating is Relatively Low. This means Nassau County faces higher natural disaster risk than the typical county in New York.

Yes, Nassau County's flooding risk is at the 98th percentile nationally. This places it in the top quartile for this hazard type.

FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.

Nassau County's composite risk score of 97th percentile is above the New York state average of 69th percentile. This elevated risk is driven by flooding exposure (98th percentile), along with earthquake and hurricane and tornado risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.