Nassau County, NY
FEMA National Risk Index scores, disaster declarations & hazard data
Nassau County has experienced 31 federally declared disasters since 1965, most recently Severe Storm And Flooding in 2024. Its overall natural hazard risk is rated Relatively High — higher risk than most US counties.
Nassau County's highest-rated hazards are winter weather, ice storm, and coastal flooding, with its top risk rated "Very High" by FEMA's National Risk Index. Recorded storm events have decreased 35% over the past five years compared to the prior five-year period. Community vulnerability is relatively low (28th percentile nationally), indicating stronger recovery capacity than most US counties.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Nassau County has been designated in 31 declarations since 1965, covering 8 disaster types including hurricane (12), severe storm (6), flood (4).
| Year | Type | Event name |
|---|---|---|
| 2024 | Flood | Severe Storm And Flooding |
| 2021 | Hurricane | Tropical Storm Isaias |
| 2021 | Hurricane | Remnants Of Hurricane Ida |
| 2021 | Hurricane | Remnants Of Hurricane Ida |
| 2021 | Hurricane | Hurricane Henri |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2013 | Hurricane | Hurricane Sandy |
| 2013 | Hurricane | Hurricane Sandy |
| 2011 | Severe Storm | Severe Winter Storm And Snowstorm |
Showing the 10 most recent of 31 total declarations since 1965.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Very Low | 43.6 | 0 | 0 | — |
| Inland Flooding | Relatively High | 98.2 | 76 | 0 | $8.0M |
| Coastal Flooding | Very High | 98.4 | 36 | 0 | — |
| Earthquake | Relatively Moderate | 96.5 | — | — | — |
| Heat Wave | Relatively Moderate | 96 | 2 | 0 | — |
| Tornado | Relatively Moderate | 76.2 | 1 | 0 | $300K |
| Hurricane | Relatively High | 95.4 | 0 | 0 | — |
| Hail | Very Low | 23.4 | 8 | 0 | — |
| Strong Wind | Relatively High | 97.1 | 0 | 0 | — |
| Winter Weather | Very High | 98.9 | 0 | 0 | — |
| Ice Storm | Very High | 98.7 | — | — | — |
| Cold Wave | Relatively High | 92.7 | — | — | — |
| Lightning | Very High | 97.3 | 12 | 0 | $85K |
| Drought | Very Low | 17.5 | 0 | 0 | — |
| Landslide | Relatively Low | 75.9 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Insufficient Data | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Nassau County ranks in the 28th percentile (Low) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 28th | Low |
| Socioeconomic status | 13th | Very low |
| Household characteristics | 17th | Very low |
| Racial & ethnic minority status | 81st | High |
| Housing type & transportation | 56th | Moderate |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 23rd | Relatively Low |
| Risk to homes | 24th | Relatively Low |
| Buildings in direct exposure zone | 7.4% | — |
NOAA tracked 135 weather events in this county over 2016–2025: 82 in 2016–20 vs 53 in 2021–25 (-35% — frequency decreasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Nassau County?
According to the FEMA National Risk Index, the highest-risk hazards in Nassau County, New York are winter weather, ice storm, and coastal flooding. The county's overall natural hazard risk is rated Relatively High — higher risk than most US counties.
Has Nassau County received federal disaster declarations?
Yes. Nassau County has received 31 federal disaster declarations since 1965, including declarations in 2024. The most common disaster type on record is hurricane (12 declarations).
Has Nassau County had any FEMA disaster declarations in 2024, 2025, or 2026?
Yes. Recent federal disaster declarations for Nassau County include Severe Storm And Flooding (2024). See the declarations table above for the full history since 1965.
How does Nassau County's natural hazard risk compare to nearby counties?
Among neighboring counties, Kings County, NY has the highest overall natural hazard risk (Relatively High) and Hudson County, NJ has the lowest (Relatively High). Nassau County is rated Relatively High overall.
How is Nassau County's composite disaster risk index calculated?
Nassau County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Nassau County's composite score of 97 means its overall natural hazard risk is higher than 97% of US counties.