Plymouth County, Massachusetts Natural Disaster Risk
FEMA National Risk Index assessment · MA
MediumComposite Risk Score
National percentile: 90th
Plymouth County faces medium composite natural disaster risk (NRI Risk Index score 90.4, 90th national percentile), driven primarily by coastal flood and riverine flood exposure. Expected annual loss across all 18 hazard types is $114M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Plymouth County carries a medium composite natural disaster risk, with a National Risk Index score of 90.4 out of 100 — placing it in the 90th national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Plymouth County's expected losses come from coastal flood (seawater inundation from storm surge, high tides, and rising sea levels) at Very High risk — $14M in expected annual loss and about 7.14 events per year; riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at Medium risk — $71M in expected annual loss and about 2.32 events per year; and strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at High risk — $3M in expected annual loss and about 0.66 events per year. Across all hazards, FEMA estimates $114M in expected annual loss for a population of 530K.
Beyond physical exposure, Plymouth County has a very low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The federal record bears this out: Plymouth County has received 32 federal disaster declarations since 1972, including 9 for hurricane events and 7 for severe storm events. The most recent was Hurricane Lee (hurricane), declared in September 2023.
Among 14 Massachusetts counties, Plymouth County ranks #7 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Coastal Flood | Very High | 7.14 / yr | $14M |
| Riverine Flood | Medium | 2.32 / yr | $71M |
| Strong Wind | High | 0.66 / yr | $3M |
| Hurricane | Medium | 0.17 / yr | $11M |
| Lightning | High | 18.66 / yr | $2M |
| Earthquake | Low | 0.00 / yr | $5M |
| Heat Wave | Medium | 5.09 / yr | $3M |
| Ice Storm | High | 0.62 / yr | $690K |
| Drought | Medium | 3.15 / yr | $690K |
| Cold Wave | Low | 1.03 / yr | $2M |
| Landslide | Very Low | 0.19 / yr | $4K |
| Wildfire | Very Low | 0.00 / yr | $78K |
| Tornado | Low | 0.14 / yr | $2M |
| Winter Weather | Low | 11.14 / yr | $60K |
| Hail | Very Low | 1.28 / yr | $27K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Plymouth County has received 32 federal disaster declarations since 1972, most recently Hurricane Lee in September 2023. Most frequent causes: Hurricane (9), Severe Storm (7), Snowstorm (6).
| Declared | Type | Disaster |
|---|---|---|
| September 2023 | Hurricane | Hurricane Lee |
| April 2022 | Snowstorm | Severe Winter Storm and Snowstorm |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| June 2018 | Severe Storm | Severe Winter Storm and Flooding |
| April 2015 | Severe Storm | Severe Winter Storm, Snowstorm, and Flooding |
| April 2013 | Severe Storm | Severe Winter Storm, Snowstorm, and Flooding |
| December 2012 | Hurricane | Hurricane Sandy |
| October 2012 | Hurricane | Hurricane Sandy |
| September 2011 | Hurricane | Tropical Storm Irene |
Showing the 10 most recent of 32 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Plymouth County?
Plymouth County has a composite FEMA National Risk Index score of 90.4 out of 100, placing it in the Medium category and the 90th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Plymouth County?
The three highest-rated hazards are Coastal Flood (Very High, $14M EAL), Riverine Flood (Medium, $71M EAL), Strong Wind (High, $3M EAL). These account for most of the county's expected annual losses.
How does Plymouth County compare to other Massachusetts counties?
Plymouth County ranks #7 of 14 Massachusetts counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Plymouth County had?
FEMA records 32 federal disaster declarations for Plymouth County since 1972, most often 9 for hurricane events and 7 for severe storm events. The most recent was Hurricane Lee, declared in September 2023.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Plymouth County's $114M EAL is a statistical average, not a guarantee for any specific year or address.