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

Union County Disaster Risk

Union County, Iowa

FEMA Risk Rating

Relatively Low

National Percentile

50th

of 3,144 counties

State Rank

#27

of 99 (1 = highest risk)

Flood Risk

30th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 30% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 50% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 57% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 24% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 11% of US counties

Risk Overview

About Natural Disaster Risk in Union County, Iowa

Union County risk moderately above average

Union County's composite risk score of 49.52 with a Relatively Low rating exceeds the national average by roughly 25 percent. This indicates moderate but manageable exposure to natural hazards.

Union ranks above Iowa's middle threshold

At 49.52, Union County exceeds Iowa's state average of 39.68, placing it in the upper-middle range of the state's risk profile. Several Iowa counties rank lower, while others face substantially steeper hazards.

Union faces moderate regional risks

Union County's 49.52 score sits between safer Taylor County (38.49) and higher-risk Sioux County (52.39) and Story County (68.83). It represents a moderate risk level for south-central Iowa.

Tornadoes and wildfires demand attention

Tornado risk (57.09) and wildfire risk (49.84) represent Union County's primary hazards, while flood risk (30.09) and earthquake risk (24.20) pose secondary concerns. The combination of wind and fire threats requires active preparedness.

Cover wind, fire, and flood exposure

Union County residents should ensure homeowner's policies include robust tornado and wind coverage, plus consider flood insurance for extra protection. Maintain defensible space around your home to reduce wildfire risk.

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

  1. #1
    TornadoPrepare
    57th percentile
  2. #2
    WildfirePrepare
    50th percentile
  3. #3
    FloodPrepare
    30th percentile

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

Local Resources

Risk Advisory: Union County

Risk Verdict

Union County ranks at the 50th percentile nationally for natural disaster risk — below the median for U.S. counties. A preparedness foundation — alert registration, household communication plan, and a basic supply review — costs little and remains valuable even at Union County's favorable 50th percentile ranking.

Hazard Breakdown

Tornado risk is Union County's dominant natural hazard, ranked at the 57th percentile nationally under FEMA's National Risk Index. Wildfire ranks second at the 50th percentile nationally. Additional tracked hazards include flood (30th percentile), earthquake (24th percentile), hurricane (11th percentile).

Preparedness Context

Union County ranks at the 57th percentile nationally for tornado exposure. Unlike many slow-onset hazards, tornadoes in Union County can reach full intensity in minutes; a pre-practiced household shelter plan matters far more than stockpiled supplies. Wildfire is the second hazard driver for Union County at the 50th percentile nationally, meaning households should maintain awareness of both severe-weather and wildfire-specific warning systems. Union County county emergency management typically publishes annual severe-weather preparedness guides tailored to local tornado patterns; households benefit from reviewing these before storm season begins each spring.

Regional Context

Compared to other Iowa counties, Union County runs 9.8 composite risk points higher than the state mean — reflecting above-average hazard concentration in this area.

Is your household prepared for Union 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 Union County, IA?
Union County has a FEMA National Risk Index rating of Relatively Low, placing it in the 50th 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 Union County?
Union County is evaluated for five major natural hazard types: tornado (57th percentile), wildfire (50th percentile), flooding (30th percentile), earthquake (24th percentile), hurricane (11th percentile). The highest-risk hazard is tornado at the 57th 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 Union County risk compare to the Iowa average?
Union County's composite risk percentile is 50th, compared to the Iowa state average of 40th percentile. The state's overall risk rating is Very Low. This means Union County faces higher natural disaster risk than the typical county in Iowa.
Is Union County at risk for tornado?
Yes, Union County's tornado risk is at the 57th percentile nationally. This is above the national median. For flooding specifically, Union County is at the 30th 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 Union County higher risk than average?
Union County's composite risk score of 50th percentile is above the Iowa state average of 40th percentile. This elevated risk is driven by tornado exposure (57th percentile). Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Adair County

Iowa

-0.0

Relatively Low

49th percentile

Delaware County

Iowa

+0.2

Relatively Low

50th percentile

Plymouth County

Iowa

-0.3

Relatively Low

49th 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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