Nantucket County, Massachusetts: Natural Disaster Risk and History
Nantucket County, Massachusetts has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 38.7 out of 100, higher than about 38% of US counties, with hurricanes, coastal flooding and earthquakes scoring highest of its 18 hazards and $23 million a year in expected losses.
OpenFEMA lists 18 federal disaster declarations that included Nantucket County since 1972, not counting 2 for COVID-19; the latest is EM-3599-MA (Hurricane Lee, declared 15 September 2023). NOAA's Storm Prediction Center has no tornado on record touching Nantucket County from 1950 to 2025.
Live weather alerts for Massachusetts All official warnings Latest FEMA declarations
Population 14,255 Buildings worth $7.0 billion Area 307 sq mi Risk rank in Massachusetts 13 of 14 FIPS 25019
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Hurricane | Relatively Moderate | 90.9 | $17 million | about once every 5.1 years | 46 |
| Coastal flooding | Relatively Moderate | 70.0 | $2.1 million | about 3.7 a year | — |
| Earthquake | Very Low | 22.4 | $65,411 | rarer than once in 1,000 years | — |
| Drought | Very Low | 21.9 | $11,846 | about 1.1 a year | 28 |
| Inland flooding | Very Low | 16.6 | $3.8 million | about once every 4.0 years | 7 |
| Wildfire | Very Low | 13.0 | $8,227 | rarer than once in 1,000 years | — |
| Lightning | Very Low | 6.1 | $36,412 | about 14 a year | 9,228 strikes |
| Cold wave | Very Low | 4.3 | $15,671 | about once every 3.2 years | 6 |
| Tornado | Very Low | 4.1 | $25,175 | about once every 117 years | 0 |
| Hail | Very Low | 4.0 | $16,575 | about once every 5.9 years | 8.2 |
| Landslide | Very Low | 2.3 | $4 | about once every 174 years | — |
| Strong wind | Very Low | 2.0 | $17,433 | about once every 12 years | 1 |
| Winter weather | Very Low | 1.9 | $1,631 | about 5.8 a year | 111 |
| Ice storm | Very Low | 0.1 | $162 | about once every 67 years | 0 |
| Heat wave | No Rating | 0.0 | — | — | 0 |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Insufficient Data | — | — | — | — |
| Volcanic activity | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 18
Most common: Hurricane 7, Snowstorm 4, Severe Storm 3, Coastal Storm 2.
| Decade | Declarations | Incident types |
|---|---|---|
| 1970s | 2 | Flood, Fishing Losses |
| 1990s | 5 | Snowstorm ×2, Coastal Storm ×2, Hurricane |
| 2000s | 3 | Snowstorm ×2, Hurricane |
| 2010s | 7 | Hurricane ×4, Severe Storm ×3 |
| 2020s | 1 | Hurricane |
The last 10
Widest declarations that included Nantucket County
- Hurricane Lee (2023, EM-3599-MA): 14 Massachusetts counties designated.
- Severe Winter Storm, Snowstorm, and Flooding (2013, DR-4110-MA): 14 Massachusetts counties designated.
- Hurricane Sandy (2012, EM-3350-MA): 14 Massachusetts counties designated.
Named storms in its declarations: Hurricane Lee (2023), Hurricane Sandy (2012), Hurricane Irene (2011), Hurricane Earl (2010), Hurricane Katrina (2005), Hurricane Bob (1991).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Massachusetts also had 6 statewide declarations with no county list.
Tornado record since 1950 0
No tornado in NOAA's Storm Prediction Center record touched Nantucket County between 1950 and 2025. That does not mean one cannot happen.
How Nantucket County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Nantucket County (this page) | — | Very Low | 38.7 | Hurricane |
| Dukes County | 51 km | Very Low | 16.8 | Hurricane |
| Barnstable County | 53 km | Relatively Moderate | 89.1 | Coastal flooding |
| Plymouth County | 97 km | Relatively Moderate | 90.4 | Coastal flooding |
| Newport County, RI | 102 km | Very Low | 36.4 | Hurricane |
| Bristol County | 105 km | Relatively Moderate | 89.9 | Inland flooding |
Nearest by distance between county centres. Every county in Massachusetts, ranked.
Vulnerability and resilience
| Social vulnerability | Very Low 10.6 |
|---|---|
| Community resilience | Very High 99.0 |
| Community risk factor | 0.55 |
| Expected annual loss, all hazards | $23 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Nantucket County's main hazards
- Right now: National Weather Service alerts for Massachusetts · all official warnings on Global Incident Tracker.
- Hurricane: Is there a hurricane now? · Cyclone preparation
- Coastal flooding: Flood safety: why shallow water kills · Hurricanes and storms now
- Earthquake: Earthquakes today · Earthquake safety guide
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Nantucket County
What natural disasters is Nantucket County, Massachusetts most at risk from?
Nantucket County, Massachusetts has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 38.7 out of 100, higher than about 38% of US counties, with hurricanes, coastal flooding and earthquakes scoring highest of its 18 hazards and $23 million a year in expected losses.
How many federal disaster declarations has Nantucket County had?
OpenFEMA lists 18 federal disaster declarations that included Nantucket County since 1972, not counting 2 for COVID-19; the latest is EM-3599-MA (Hurricane Lee, declared 15 September 2023). Another 6 Massachusetts declarations were made statewide without a county list.
How many tornadoes have hit Nantucket County?
NOAA's Storm Prediction Center has no tornado on record touching Nantucket County from 1950 to 2025.
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.