Natural disaster risk in Massachusetts, by county
All 14 counties in Massachusetts, ranked by FEMA's National Risk Index composite risk score, with each one's highest-rated hazard. Other states
At a glance
Highest overall risk: Middlesex County (relatively high, score 96.9). Lowest: Dukes County (very low, score 16.8).
Top hazards in Massachusetts
| Hazard | Counties rated relatively high or very high | Average score |
|---|---|---|
| Inland (riverine) flooding | 7 of 14 | 81.3 |
| Ice storm | 7 of 14 | 72.1 |
| Lightning | 7 of 14 | 71.7 |
| Hurricane | 6 of 14 | 89.4 |
| Strong wind | 6 of 14 | 67.3 |
All counties, highest risk first
| # | County | Overall risk | Highest-rated hazard |
|---|---|---|---|
| 1 | Middlesex County | Relatively high 96.9 | Ice storm (very high) |
| 2 | Essex County | Relatively high 95.6 | Coastal flooding (very high) |
| 3 | Suffolk County | Relatively moderate 93.5 | Lightning (very high) |
| 4 | Worcester County | Relatively moderate 93.5 | Ice storm (very high) |
| 5 | Hampden County | Relatively moderate 92.8 | Inland (riverine) flooding (relatively high) |
| 6 | Norfolk County | Relatively moderate 92 | Inland (riverine) flooding (relatively high) |
| 7 | Plymouth County | Relatively moderate 90.4 | Coastal flooding (very high) |
| 8 | Bristol County | Relatively moderate 89.9 | Inland (riverine) flooding (relatively high) |
| 9 | Barnstable County | Relatively moderate 89.1 | Coastal flooding (very high) |
| 10 | Berkshire County | Relatively moderate 84 | Inland (riverine) flooding (relatively moderate) |
| 11 | Hampshire County | Relatively low 69.9 | Hurricane (relatively moderate) |
| 12 | Franklin County | Relatively low 60.7 | Ice storm (relatively moderate) |
| 13 | Nantucket County | Very low 38.7 | Hurricane (relatively moderate) |
| 14 | Dukes County | Very low 16.8 | Hurricane (relatively low) |
How to read these ratings
- Ratings run in five steps: very low, relatively low, relatively moderate, relatively high and very high. They compare a county with every other US county; they are not a measure of danger on their own.
- Scores run from 0 to 100 and are national percentiles. The bar shows the score: a score of 80 means a higher value than 80% of US counties.
- Overall risk combines the expected annual loss with social vulnerability and community resilience.
- Expected annual loss is the average yearly loss to buildings, people and agriculture the model expects from all 18 hazards.
- Social vulnerability describes how hard it may be for people to prepare for and recover from a disaster. Higher is worse.
- Community resilience describes a community's ability to prepare, adapt and recover. Higher is better.
- "Not applicable" means FEMA does not model that hazard there (for example, hurricanes far inland).
About this data
Source: FEMA National Risk Index, version 1.20, released December 2025, published by the Federal Emergency Management Agency (US public domain). About the National Risk Index. The index is a model of relative risk built from historical hazard records, what is exposed and community factors. It is not a forecast, it does not describe any single property, and it is not insurance or financial advice. For decisions about a specific address, check FEMA's flood maps and your local emergency management office.
Questions
Which county in Massachusetts has the highest natural disaster risk?
Middlesex County has the highest composite risk score in Massachusetts in FEMA's National Risk Index: 96.9, rated relatively high.
Which county in Massachusetts has the lowest natural disaster risk?
Dukes County has the lowest composite risk score in Massachusetts: 16.8, rated very low. A low score means lower modelled risk compared with other US counties, not no risk.
What natural disasters is Massachusetts most at risk from?
Across Massachusetts, the hazards rated highest in the most counties are inland (riverine) flooding, ice storm, lightning, according to FEMA's National Risk Index. Each county page lists all 18 hazards.
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