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

Brown County Disaster Risk

Brown County, South Dakota

FEMA Risk Rating

Relatively Low

National Percentile

74th

of 3,144 counties

State Rank

#4

of 66 (1 = highest risk)

Flood Risk

63th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 63% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 77% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 70% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 28% of US counties

Risk Overview

About Natural Disaster Risk in Brown County, South Dakota

Brown faces well-above-average risk

Brown County's composite risk score of 73.54 represents the highest among the eight profiled counties and exceeds the national average by 173%. Your county confronts multiple severe natural disasters that demand serious preparedness and insurance protection.

South Dakota's highest-risk county

Brown County ranks as the most hazard-exposed county in South Dakota with a composite score of 73.54, nearly tripling the state average of 26.84. No other South Dakota county faces comparable overall natural disaster risk.

Far riskier than surrounding counties

Brown's composite score of 73.54 dramatically exceeds nearby Brule County (58.72) and Buffalo County (13.74). Brown County stands alone in northeastern South Dakota as an exceptionally high-risk natural disaster zone.

Tornadoes, floods, and wildfires converge

Tornado risk (70.13), flood risk (63.07), and wildfire risk (77.07) all exceed 60 in Brown County, creating a perfect storm of natural disaster threats. This convergence of three major hazards makes Brown County one of America's most disaster-vulnerable regions.

Comprehensive multi-hazard insurance critical

Brown County residents must prioritize comprehensive homeowners insurance with tornado, windstorm, and wildfire coverage, plus mandatory flood insurance from the National Flood Insurance Program. Professional installation of a safe room or residential storm shelter is highly recommended given the severe convergence of multiple hazards.

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

Preparedness Guide

What to Prepare for in Brown County

Top Hazards by Exposure

  1. #1
    WildfirePrepare
    77th percentile
  2. #2
    TornadoPrepare
    70th percentile
  3. #3
    FloodPrepare
    63th percentile

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

Local Resources

Risk Advisory: Brown County

Risk Verdict

Brown County ranks at the 74th percentile nationally for natural disaster risk — below the median for U.S. counties. Residents are encouraged to understand which hazards dominate locally and tailor their preparedness accordingly.

Hazard Breakdown

Wildfire risk is Brown County's dominant natural hazard, ranked at the 77th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 70th percentile nationally. Additional tracked hazards include flood (63th percentile), earthquake (28th percentile).

Preparedness Context

Brown County's dominant hazard is wildfire, ranked at the 77th percentile nationally. Maintaining at least 30 feet of lean, clean vegetation around structures in Brown County and keeping gutters clear of debris significantly reduces ignition risk from wind-driven embers. A secondary tornado exposure at the 70th percentile nationally means Brown County residents face hazards from two distinct natural peril categories during different seasons. Brown County's households benefit from reviewing homeowners insurance before fire season, specifically whether the policy covers replacement cost rather than actual cash value, and whether it includes additional living expenses if displacement is required.

Regional Context

Compared to other South Dakota counties, Brown County runs 46.7 composite risk points higher than the state mean — reflecting above-average hazard concentration in this area.

Is your household prepared for Brown 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 Brown County, SD?
Brown County has a FEMA National Risk Index rating of Relatively Low, placing it in the 74th 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 Brown County?
Brown County is evaluated for five major natural hazard types: wildfire (77th percentile), tornado (70th percentile), flooding (63th percentile), earthquake (28th percentile). The highest-risk hazard is wildfire at the 77th 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 Brown County risk compare to the South Dakota average?
Brown County's composite risk percentile is 74th, compared to the South Dakota state average of 27th percentile. The state's overall risk rating is Very Low. This means Brown County faces higher natural disaster risk than the typical county in South Dakota.
Is Brown County at risk for wildfire?
Yes, Brown County's wildfire risk is at the 77th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Brown County is at the 63th 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.
Why is Brown County higher risk than average?
Brown County's composite risk score of 74th percentile is above the South Dakota state average of 27th percentile. This elevated risk is driven by wildfire exposure (77th percentile), along with tornado and flooding risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Pennington County

South Dakota

+5.0

Relatively Low

79th percentile

Dewey County

South Dakota

+5.2

Relatively Low

79th percentile

Yankton County

South Dakota

-10.2

Relatively Low

63th percentile

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.

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