Bristol County, Massachusetts Natural Disaster Risk
FEMA National Risk Index assessment · MA
MediumComposite Risk Score
National percentile: 90th
Bristol County faces medium composite natural disaster risk (NRI Risk Index score 89.9, 90th national percentile), driven primarily by riverine flood and hurricane exposure. Expected annual loss across all 18 hazard types is $87M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Bristol County carries a medium composite natural disaster risk, with a National Risk Index score of 89.9 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 Bristol County's expected losses come from riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at High risk — $62M in expected annual loss and about 3.32 events per year; hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at Medium risk — $10M in expected annual loss and about 0.19 events per year; and earthquake (ground shaking from sudden movement along geologic faults) at Low risk — $4M in expected annual loss and about 0.00 events per year. Across all hazards, FEMA estimates $87M in expected annual loss for a population of 579K.
Beyond physical exposure, Bristol County has a 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 county's disaster history tells the same story: Bristol County has received 30 federal disaster declarations since 1972, including 9 for hurricane events and 8 for severe storm events. The most recent was Severe Storms and Flooding (flood), declared in May 2024.
Among 14 Massachusetts counties, Bristol County ranks #8 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Riverine Flood | High | 3.32 / yr | $62M |
| Hurricane | Medium | 0.19 / yr | $10M |
| Earthquake | Low | 0.00 / yr | $4M |
| Heat Wave | Medium | 5.07 / yr | $3M |
| Strong Wind | High | 0.74 / yr | $2M |
| Ice Storm | High | 0.60 / yr | $558K |
| Lightning | Medium | 20.00 / yr | $650K |
| Cold Wave | Medium | 0.93 / yr | $2M |
| Coastal Flood | Medium | 3.72 / yr | $922K |
| Drought | Low | 4.09 / yr | $295K |
| Tornado | Low | 0.11 / yr | $1M |
| Landslide | Very Low | 0.13 / yr | $1K |
| Winter Weather | Low | 11.08 / yr | $55K |
| Wildfire | Very Low | 0.00 / yr | $24K |
| Hail | Very Low | 1.30 / yr | $22K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Bristol County has received 30 federal disaster declarations since 1972, most recently Severe Storms and Flooding in May 2024. Most frequent causes: Hurricane (9), Severe Storm (8), Snowstorm (6).
| Declared | Type | Disaster |
|---|---|---|
| May 2024 | Flood | Severe Storms and Flooding |
| 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 |
| April 2013 | Terrorist | Explosions |
| December 2012 | Hurricane | Hurricane Sandy |
Showing the 10 most recent of 30 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Bristol County?
Bristol County has a composite FEMA National Risk Index score of 89.9 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 Bristol County?
The three highest-rated hazards are Riverine Flood (High, $62M EAL), Hurricane (Medium, $10M EAL), Earthquake (Low, $4M EAL). These account for most of the county's expected annual losses.
How does Bristol County compare to other Massachusetts counties?
Bristol County ranks #8 of 14 Massachusetts counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Bristol County had?
FEMA records 30 federal disaster declarations for Bristol County since 1972, most often 9 for hurricane events and 8 for severe storm events. The most recent was Severe Storms and Flooding, declared in May 2024.
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. Bristol County's $87M EAL is a statistical average, not a guarantee for any specific year or address.