riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Sully County Disaster Risk

Sully County, South Dakota

FEMA Risk Rating

Very Low

National Percentile

6th

of 3,144 counties

State Rank

#56

of 66 (1 = highest risk)

Flood Risk

14th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 14% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 71% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 15% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 7% of US counties

Risk Overview

About Natural Disaster Risk in Sully County, South Dakota

Sully County sits safely below national risk

Sully County's composite risk score of 6.33 places it in the Very Low category and significantly below the national average. This exceptional safety profile reflects minimal exposure to major natural disaster hazards.

Among South Dakota's safest counties

At 6.33, Sully County ranks near the bottom of the risk scale in South Dakota, substantially below the state average of 26.84. Only a handful of counties statewide match this level of disaster resilience.

Sully is the calm center of its region

Sully County's 6.33 score places it among the safest neighbors, slightly higher than Stanley County (5.06) but far below Todd County (36.61) and Tripp County (36.45). It represents an island of stability in a more volatile regional landscape.

Wildfires present the main hazard

Wildfire risk is Sully County's leading concern at 70.58, though tornado (14.60) and flood (14.12) risks remain comparatively low. Earthquake exposure is minimal (6.77), contributing to the county's overall safety.

Maintain wildfire insurance and preparedness

Sully County residents should prioritize fire insurance and defensible space around structures, even as most other disaster risks remain minimal. Standard homeowners coverage supplemented with fire protection strategies provides adequate peace of mind.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Sully County

Top Hazards by Exposure

  1. #1
    WildfirePrepare
    71th percentile
  2. #2
    TornadoPrepare
    15th percentile
  3. #3
    FloodPrepare
    14th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Sully County

Risk Verdict

Sully County's overall natural disaster score at the 6th percentile puts it well below the national median for hazard exposure. Sully County's 6th percentile ranking is favorable, though every county carries at least one natural hazard worth knowing — reviewing the specific risks listed above helps households focus their preparedness where it matters most.

Hazard Breakdown

Wildfire risk is Sully County's dominant natural hazard, ranked at the 71th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 15th percentile nationally. Additional tracked hazards include flood (14th percentile), earthquake (7th percentile).

Preparedness Context

With wildfire ranked at the 71th percentile nationally, Sully County is in a zone where air quality can deteriorate rapidly before structures are threatened. An N95 respirator and a HEPA air purifier are practical items for Sully County households to have on hand before fire season. Alongside wildfire, tornado at the 15th percentile nationally means a multi-season preparedness mindset — fire season and flood or storm season often require different household plans. Defensible space, insurance review, and an evacuation plan are the three preparedness pillars for Sully County households — and the insurance review is the one most often deferred by Sully County residents and most costly to skip when a fire event actually occurs.

Regional Context

Sully County's composite risk score sits 20.5 points below the South Dakota county average, reflecting a more favorable hazard environment than the state typical.

Is your household prepared for Sully County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Sully County, SD?
Sully County has a FEMA National Risk Index rating of Very Low, placing it in the 6th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Sully County?
Sully County is evaluated for five major natural hazard types: wildfire (71th percentile), tornado (15th percentile), flooding (14th percentile), earthquake (7th percentile). The highest-risk hazard is wildfire at the 71th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Sully County risk compare to the South Dakota average?
Sully County's composite risk percentile is 6th, compared to the South Dakota state average of 27th percentile. The state's overall risk rating is Very Low. This means Sully County faces lower natural disaster risk than the typical county in South Dakota.
Is Sully County at risk for wildfire?
Yes, Sully County's wildfire risk is at the 71th percentile nationally. This is above the national median. For flooding specifically, Sully County is at the 14th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Is Sully County a safe place to live?
Sully County's composite risk score of 6th percentile is below the South Dakota state average of 27th percentile, indicating relatively lower exposure to natural hazards. However, no county is completely risk-free. The primary hazard type is wildfire at the 71th percentile. Residents should still maintain emergency preparedness plans and appropriate insurance coverage.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.