Massachusetts tornado risk
Essex County has the highest tornado risk in Massachusetts, scoring 92.4 out of 100 — rated "Relatively High" by FEMA's National Risk Index. Recorded tornado events across Massachusetts have increased 31% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Essex County | 92.4 | Relatively High | 0 |
| 2 | Middlesex County | 90.1 | Relatively Moderate | 4 |
| 3 | Hampden County | 82.7 | Relatively Moderate | 1 |
| 4 | Worcester County | 82.2 | Relatively Moderate | 13 |
| 5 | Suffolk County | 75.3 | Relatively Moderate | 0 |
| 6 | Norfolk County | 69 | Relatively Moderate | 4 |
| 7 | Bristol County | 52.1 | Relatively Low | 5 |
| 8 | Berkshire County | 48.8 | Relatively Low | 1 |
| 9 | Plymouth County | 48.2 | Relatively Low | 1 |
| 10 | Hampshire County | 46.9 | Relatively Low | 1 |
| 11 | Barnstable County | 45.5 | Relatively Low | 6 |
| 12 | Franklin County | 31.6 | Relatively Low | 1 |
| 13 | Dukes County | 10.7 | Very Low | 0 |
| 14 | Nantucket County | 4.1 | Very Low | 0 |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Tornado risk nationally:
Other hazard risks in Massachusetts:
Frequently asked questions
What is the highest tornado risk county in Massachusetts?
Essex County, MA has the highest tornado risk in Massachusetts, with a FEMA National Risk Index score of 92.4 out of 100 (rated "Relatively High").
What causes tornado risk in Massachusetts?
Tornado risk concentrates in the central and southern plains ("Tornado Alley") and the Southeast ("Dixie Alley"), where atmospheric conditions favor supercell thunderstorm development. The highest scores often belong to counties with significant mobile home and manufactured housing stock, which carries disproportionate tornado mortality risk.