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

Lyman County Disaster Risk

Lyman County, South Dakota

FEMA Risk Rating

Very Low

National Percentile

26th

of 3,144 counties

State Rank

#28

of 66 (1 = highest risk)

Flood Risk

29th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 29% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 70% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 28% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 14% of US counties

Risk Overview

About Natural Disaster Risk in Lyman County, South Dakota

Lyman County's risk profile mirrors South Dakota's average

Lyman County's composite risk score of 26.46 aligns closely with South Dakota's state average of 26.84, earning a "Very Low" national rating. This stability masks important pockets of hazard exposure: wildfire risk (69.53) substantially exceeds the county's overall profile. The county's low composite score reflects balanced—rather than negligible—risk across multiple hazard types.

Lyman ranks near the middle of South Dakota counties

Lyman County's composite risk score of 26.46 places it near the state average of 26.84, neither among the highest nor lowest-risk counties in South Dakota. The county's wildfire risk (69.53) stands out as notably elevated within its otherwise moderate profile. For residents, this means attention to wildfire preparedness is warranted, even as overall disaster risk remains relatively contained.

Lyman's wildfire risk outpaces similar nearby areas

Lyman County's wildfire risk (69.53) substantially exceeds that of neighboring McPherson County (70.36), though the two counties share similar composite scores. Compared to Marshall County (76.62 wildfire risk), Lyman faces somewhat lower wildfire exposure despite higher overall composite risk. Understanding these hazard-specific variations helps target your insurance and preparedness efforts.

Wildfires and tornadoes present measurable threats

Lyman County's wildfire risk (69.53) is the dominant hazard concern, substantially exceeding the county's composite score and reflecting vulnerability to grassland and structural fires. Tornado risk (27.64) ranks second, remaining below state and national averages but still present. Flood risk (29.13) adds a third consideration, particularly for properties near drainage areas.

Prioritize wildfire insurance and defensible space

Lyman County's elevated wildfire risk (69.53) makes it essential to maintain defensible space around your home and verify that your homeowners policy covers wildfire damage—some carriers exclude or limit this coverage in high-risk areas. Ensure you understand your policy's wind and hail coverage as well, given tornado exposure. A separate flood insurance policy is advisable for any property in a mapped flood zone or with drainage concerns.

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

Preparedness Guide

What to Prepare for in Lyman County

Top Hazards by Exposure

  1. #1
    WildfirePrepare
    70th percentile
  2. #2
    FloodPrepare
    29th percentile
  3. #3
    TornadoPrepare
    28th percentile

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

Risk Advisory: Lyman County

Risk Verdict

Compared to the nation's 3,144 counties, Lyman County ranks at the 26th percentile for natural disaster risk — toward the safer end of the spectrum. A 26th percentile score positions Lyman County among the nation's lower-risk counties, a genuinely favorable outcome — one that simple, low-cost preparedness habits can reinforce further.

Hazard Breakdown

Wildfire risk is Lyman County's dominant natural hazard, ranked at the 70th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 29th percentile nationally. Additional tracked hazards include tornado (28th percentile), earthquake (14th percentile).

Preparedness Context

Lyman County sits at the 70th percentile for wildfire exposure. Signing up for Lyman County's county emergency alert system and knowing the pre-planned evacuation route before conditions deteriorate are the two highest-value preparedness actions for residents here. A secondary flood exposure at the 29th percentile nationally means Lyman County residents face hazards from two distinct natural peril categories during different seasons. In Lyman County, wildfire smoke often precedes the flame front by hours or days; households benefit from tracking EPA's AirNow.gov and having HEPA air filtration available as a first line of indoor protection when air quality alerts are issued.

Regional Context

Lyman County sits within 0.4 composite points of the South Dakota state average, suggesting the county's hazard exposure is representative of the broader regional pattern.

Is your household prepared for Lyman 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 Lyman County, SD?
Lyman County has a FEMA National Risk Index rating of Very Low, placing it in the 26th 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 Lyman County?
Lyman County is evaluated for five major natural hazard types: wildfire (70th percentile), flooding (29th percentile), tornado (28th percentile), earthquake (14th percentile). The highest-risk hazard is wildfire at the 70th 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 Lyman County risk compare to the South Dakota average?
Lyman County's composite risk percentile is 26th, compared to the South Dakota state average of 27th percentile. The state's overall risk rating is Very Low. This means Lyman County faces lower natural disaster risk than the typical county in South Dakota.
Is Lyman County at risk for wildfire?
Yes, Lyman County's wildfire risk is at the 70th percentile nationally. This is above the national median. For flooding specifically, Lyman County is at the 29th 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 Lyman County a safe place to live?
Lyman County's composite risk score of 26th 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 70th 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.