Nantucket County, MA
FEMA National Risk Index scores, disaster declarations & hazard data
Nantucket County has experienced 20 federally declared disasters since 1972, most recently Hurricane Lee in 2023. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Nantucket County's highest-rated hazards are hurricane, coastal flooding, and earthquake, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Community vulnerability is relatively low (10th 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. Nantucket County has been designated in 20 declarations since 1972, covering 7 disaster types including hurricane (7), snowstorm (4), severe storm (3).
| Year | Type | Event name |
|---|---|---|
| 2023 | Hurricane | Hurricane Lee |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2018 | Severe Storm | Severe Winter Storm And Flooding |
| 2015 | Severe Storm | Severe Winter Storm, Snowstorm, And Flooding |
| 2013 | Severe Storm | Severe Winter Storm, Snowstorm, And Flooding |
| 2013 | Hurricane | Hurricane Sandy |
| 2013 | Hurricane | Hurricane Sandy |
| 2011 | Hurricane | Hurricane Irene |
| 2010 | Hurricane | Hurricane Earl |
Showing the 10 most recent of 20 total declarations since 1972.
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 | 13 | 0 | 0 | — |
| Inland Flooding | Very Low | 16.6 | 3 | 0 | — |
| Coastal Flooding | Relatively Moderate | 70 | 0 | 0 | — |
| Earthquake | Very Low | 22.4 | — | — | — |
| Heat Wave | No Rating | 0 | 0 | 0 | — |
| Tornado | Very Low | 4.1 | 0 | 0 | — |
| Hurricane | Relatively Moderate | 90.9 | 0 | 0 | — |
| Hail | Very Low | 4 | 1 | 0 | — |
| Strong Wind | Very Low | 2 | 0 | 0 | — |
| Winter Weather | Very Low | 1.9 | 0 | 0 | — |
| Ice Storm | Very Low | 0.1 | — | — | — |
| Cold Wave | Very Low | 4.3 | — | — | — |
| Lightning | Very Low | 6.1 | 3 | 0 | $12K |
| Drought | Very Low | 21.9 | 0 | 0 | — |
| Landslide | Very Low | 2.3 | 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
Nantucket County ranks in the 10th percentile (Very 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 | 10th | Very low |
| Socioeconomic status | 17th | Very low |
| Household characteristics | 4th | Very low |
| Racial & ethnic minority status | 65th | Moderate |
| Housing type & transportation | 12th | Very low |
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 | 13th | Very Low |
| Risk to homes | 17th | Very Low |
| Buildings in direct exposure zone | 32.8% | — |
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 Nantucket County?
According to the FEMA National Risk Index, the highest-risk hazards in Nantucket County, Massachusetts are hurricane, coastal flooding, and earthquake. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Nantucket County received federal disaster declarations?
Yes. Nantucket County has received 20 federal disaster declarations since 1972, including declarations in 2023. The most common disaster type on record is hurricane (7 declarations).
Has Nantucket County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Nantucket County since the start of 2024. Its most recent declaration on record is Hurricane Lee in 2023.
How does Nantucket County's natural hazard risk compare to nearby counties?
Among neighboring counties, Plymouth County, MA has the highest overall natural hazard risk (Relatively Moderate) and Dukes County, MA has the lowest (Very Low). Nantucket County is rated Very Low overall.
How is Nantucket County's composite disaster risk index calculated?
Nantucket 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. Nantucket County's composite score of 39 means its overall natural hazard risk is higher than 39% of US counties.