Union County Disaster Risk
Union County, South Dakota
FEMA Risk Rating
Very Low
National Percentile
37th
of 3,144 counties
State Rank
#21
of 66 (1 = highest risk)
Flood Risk
47th
percentile
Hazard Risk Breakdown
Flood
River, coastal, and surface flooding risk
Relatively Low
Higher than 47% of US counties
Wildfire
Wildland and wildland-urban interface fire risk
Relatively Low
Higher than 78% of US counties
Tornado
Tornado and severe thunderstorm risk
Relatively Low
Higher than 69% of US counties
Earthquake
Seismic activity and ground shaking risk
Very Low
Higher than 17% of US counties
Risk Overview
About Natural Disaster Risk in Union County, South Dakota
Union County faces above-average disaster risk
Union County's composite risk score of 37.12 exceeds the national average and ranks in the Very Low category. This represents elevated multi-hazard exposure compared to typical U.S. counties.
Union ranks among South Dakota's riskiest
At 37.12, Union County significantly exceeds the state average of 26.84, ranking among South Dakota's highest-risk counties. Very few counties statewide face comparable hazard exposure.
Union leads its region in total risk
Union County's 37.12 is the highest among its peer counties, surpassing Todd (36.61) and Tripp (36.45) to form a high-risk cluster. It faces notably greater exposure than safer neighbors like Stanley (5.06) and Sully (6.33).
Tornadoes and wildfires dominate Union's threats
Tornado risk peaks at 69.24—Union County's most severe hazard—with wildfire (77.58) following closely and flood risk (47.49) significant as well. This triple threat of tornadoes, wildfires, and flooding defines the county's disaster landscape.
Secure multi-hazard insurance protection
Union County residents should carry comprehensive homeowners insurance covering wind, fire, flood, and hail damage. Consider separate flood insurance and maintain updated inventory of belongings to expedite claims after disasters.
Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor
Preparedness Guide
What to Prepare for in Union County
Top Hazards by Exposure
Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)
Risk Advisory: Union County
Risk Verdict
Compared to the nation's 3,144 counties, Union County ranks at the 37th percentile for natural disaster risk — toward the safer end of the spectrum. Being ranked at the 37th percentile nationally is an advantage for Union County — it means fewer statistically likely events, though basic readiness ensures households are covered when exceptions occur.
Hazard Breakdown
Wildfire risk is Union County's dominant natural hazard, ranked at the 78th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 69th percentile nationally. Additional tracked hazards include flood (47th percentile), earthquake (17th percentile).
Preparedness Context
Union County sits at the 78th percentile for wildfire exposure. Signing up for Union 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 tornado exposure at the 69th percentile nationally means Union County residents face hazards from two distinct natural peril categories during different seasons. In Union 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
The South Dakota county average is 10.3 composite points below Union County's score, a gap that reflects the county's elevated position in the state's hazard distribution.
Is your household prepared for Union County's hazards?
Review FEMA's county-specific preparedness checklists and emergency planning guides.
Frequently Asked Questions
What is the natural disaster risk in Union County, SD?
What types of natural hazards affect Union County?
How does Union County risk compare to the South Dakota average?
Is Union County at risk for wildfire?
How is natural disaster risk measured?
Why is Union County higher risk than average?
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.