riskbycounty
FEMA NRI v1.20Released December 2025Methodology

South Dakota Disaster Risk

Natural disaster risk data for all 66 counties.

FEMA release

December 2025

Mean county NRI score

26.8

Counties with Data

66

of 66 total

County risk atlas

South Dakota hazard exposure by county

FEMA NRI v1.20 scores on a 0–100 relative scale. Toggle the composite and five selected hazard categories out of FEMA's 18. Flood is the higher of Coastal Flooding and Inland Flooding NRI scores.

Counties

66/66

Mean county NRI score

26.8

Risk layers

6

All South Dakota Counties

CountyNRI score
Minnehaha County89.5
Dewey County78.7
Pennington County78.6
Brown County73.5
Yankton County63.4
Lincoln County63.0
Codington County61.8
Brule County58.7
Brookings County50.1
Oglala Lakota County49.8
Meade County49.5
Lawrence County49.3
Charles Mix County48.5
Hutchinson County47.9
Beadle County47.1
McCook County43.4
Walworth County39.5
Davison County39.2
Corson County38.1
Roberts County37.8
Union County37.1
Todd County36.6
Tripp County36.5
Lake County32.6
Fall River County30.9
Day County27.6
Moody County26.9
Lyman County26.5
Ziebach County25.2
Turner County24.0
Butte County23.3
Clay County20.5
Aurora County19.6
Grant County18.9
Spink County17.7
Hughes County16.5
Custer County16.3
Gregory County16.2
Hanson County14.8
Marshall County14.5
Buffalo County13.7
McPherson County11.1
Bon Homme County10.8
Douglas County10.4
Jackson County10.2
Potter County10.0
Hamlin County10.0
Haakon County9.7
Jerauld County9.5
Faulk County8.0
Kingsbury County7.9
Edmunds County7.0
Deuel County6.9
Hyde County6.5
Hand County6.5
Sully County6.3
Bennett County5.9
Mellette County5.2
Stanley County5.1
Clark County4.5
Campbell County4.4
Sanborn County3.6
Miner County3.4
Perkins County2.6
Harding County1.5
Jones County1.3

Frequently Asked Questions

How many South Dakota county records are included?
RiskByCounty includes 66 South Dakota county records from FEMA NRI v1.20 (December 2025).
Which FEMA county ratings appear in South Dakota?
FEMA NRI v1.20 (December 2025) county rating counts for South Dakota: Very Low: 50; Relatively Low: 15; Relatively Moderate: 1; Relatively High: 0; Very High: 0; Not available: 0.
How complete are the five selected hazard fields for South Dakota?
FEMA NRI v1.20 (December 2025) availability among 66 county records: Flood: 66 of 66; Wildfire: 66 of 66; Tornado: 66 of 66; Earthquake: 66 of 66; Hurricane: 0 of 66. RiskByCounty displays five selected hazard categories out of FEMA's 18.

Official Ready.gov resource

Continue to Ready.gov for federal emergency-planning information maintained outside RiskByCounty.

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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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