riskbycounty
FEMA NRI v1.20Released December 2025Methodology

Nantucket County Disaster Risk

Nantucket County, Massachusetts

FEMA Risk Rating

Very Low

NRI score (0–100 relative scale)

38.7

FEMA composite county value

State Rank

#13

of 14, sorted high to low by RiskByCounty

Flood NRI score

70.0

higher coastal/inland value

Hazard Risk Breakdown

Five selected hazard categories out of FEMA's 18. Values are FEMA NRI v1.20 scores on a 0–100 relative scale.

Hurricane

90.9 / 100

Flood

70.0 / 100

Higher of FEMA Coastal Flooding (70.0) and Inland Flooding (16.6) NRI scores.

Earthquake

22.4 / 100

Wildfire

13.0 / 100

Tornado

4.1 / 100

FEMA NRI data summary

Selected hazard scores for Nantucket County

Among the five hazard categories displayed by RiskByCounty, hurricane has the highest NRI score for this county.

Hurricane
90.9
Flood
70.0
Earthquake
22.4
Wildfire
13.0
Tornado
4.1

Higher of FEMA Coastal Flooding and Inland Flooding NRI scores

Displayed flood score
70.0
Coastal Flooding
70.0
Inland Flooding
16.6

These five categories are a selected subset of FEMA's 18 natural hazards. FEMA's composite score and official rating are separate fields in the National Risk Index dataset.

FEMA National Risk Index documentation

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Frequently Asked Questions

How many Massachusetts county records are included?
RiskByCounty includes 14 Massachusetts county records from FEMA NRI v1.20 (December 2025).
Which FEMA county ratings appear in Massachusetts?
FEMA NRI v1.20 (December 2025) county rating counts for Massachusetts: Very Low: 2; Relatively Low: 2; Relatively Moderate: 8; Relatively High: 2; Very High: 0; Not available: 0.
How complete are the five selected hazard fields for Massachusetts?
FEMA NRI v1.20 (December 2025) availability among 14 county records: Flood: 14 of 14; Wildfire: 14 of 14; Tornado: 14 of 14; Earthquake: 14 of 14; Hurricane: 14 of 14. RiskByCounty displays five selected hazard categories out of FEMA's 18.
What FEMA NRI information is available for Nantucket County, MA?
Nantucket County has an official FEMA NRI v1.20 composite rating of Very Low and an NRI score (0–100 relative scale) of 38.7. RiskByCounty ranks it 13th of 14 Massachusetts county records when sorting the FEMA composite NRI scores from high to low.
Which selected hazard scores are shown for Nantucket County?
RiskByCounty displays five selected hazard categories out of FEMA's 18 using FEMA NRI v1.20 (December 2025). For Nantucket County, Hurricane: 90.9; Flood: 70.0; Earthquake: 22.4; Wildfire: 13.0; Tornado: 4.1.
How is flood displayed for Nantucket County?
RiskByCounty's flood display is the higher of FEMA Coastal Flooding and Inland Flooding NRI scores. For Nantucket County, Coastal Flooding is 70.0, Inland Flooding is 16.6, and the displayed flood score is 70.0.

Counties with Similar Risk

Dukes County

Massachusetts

-21.9

Very Low

NRI score 16.8

Franklin County

Massachusetts

+22.0

Relatively Low

NRI score 60.7

Hampshire County

Massachusetts

+31.2

Relatively Low

NRI score 69.9

Published by RiskByCounty

County summaries are deterministic transformations of frozen FEMA county fields. No external subject-matter reviewer is credited.

Published · Updated

Data Source

County data sourced from FEMA National Risk Index v1.20, released December 2025. Values are labeled NRI score (0–100 relative scale). RiskByCounty displays five selected hazard categories out of FEMA's 18; flood is the higher of the Coastal Flooding and Inland Flooding source scores.

RiskByCounty presents county-level source fields and deterministic arithmetic summaries.

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