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

Cass County Disaster Risk

Cass County, Iowa

FEMA Risk Rating

Relatively Low

National Percentile

60th

of 3,144 counties

State Rank

#17

of 99 (1 = highest risk)

Flood Risk

43th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 43% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 41% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 76% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 16% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 18% of US counties

Risk Overview

About Natural Disaster Risk in Cass County, Iowa

Cass County's risk ranks notably high

With a composite risk score of 60.05, Cass County ranks in the Relatively Low category but exceeds roughly 60% of U.S. counties in disaster exposure. This is Iowa's highest risk among the eight counties analyzed.

Iowa's riskiest county in this group

Cass's score of 60.05 towers 51% above Iowa's state average of 39.68, making it one of the state's highest-risk counties overall. Only a handful of Iowa counties present comparably elevated natural disaster vulnerability.

Distinctly riskier than all peers

Cass (60.05) exceeds even Carroll County (57.60) by a narrow margin, dwarfing all eastern neighbors like Bremer (24.55) and Buchanan (24.05). The county stands in a risk category almost unto itself within this regional grouping.

Compound threat from multiple hazards

Tornado risk (75.76) and flood risk (43.35) are both elevated, with wildfire risk (40.55) adding a third major concern—an unusual combination for Iowa. Earthquake risk (16.22) and hurricane risk (17.56) remain secondary but non-negligible.

Multi-hazard insurance strategy essential

Cass County residents must address tornado, flood, and wildfire risks through a layered insurance approach: ensure wind and hail coverage, evaluate flood insurance through the NFIP, and check defensible space around your home. Consider a safe room retrofit and emergency kit as foundational investments.

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

Preparedness Guide

What to Prepare for in Cass County

Top Hazards by Exposure

  1. #1
    TornadoPrepare
    76th percentile
  2. #2
    FloodPrepare
    43th percentile
  3. #3
    WildfirePrepare
    41th percentile

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

Risk Advisory: Cass County

Risk Verdict

Natural hazard pressure in Cass County is below the national midpoint, with a composite score at the 60th percentile. Proactive emergency planning and awareness of the specific hazards driving Cass County's score can meaningfully reduce household risk.

Hazard Breakdown

Tornado risk is Cass County's dominant natural hazard, ranked at the 76th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 43th percentile nationally. Additional tracked hazards include wildfire (41th percentile), hurricane (18th percentile), earthquake (16th percentile).

Preparedness Context

With tornado ranked at the 76th percentile nationally, Cass County sits in a high-exposure zone where the difference between outcomes often comes down to proximity to a reinforced interior shelter and seconds of warning time. The secondary flood hazard at the 43th percentile nationally adds seasonal complexity to Cass County's preparedness calendar, since flood and tornado risk often peak at different points in the year. For Cass County households, safe rooms certified to FEMA 320/361 standards offer the highest protection during a direct tornado hit; households without a safe room should locate the innermost lowest-floor room in their building and practice the route to it before storm season.

Regional Context

Cass County is 20.4 composite risk points above the Iowa average, indicating that residents face greater natural hazard exposure than most of their in-state neighbors.

Is your household prepared for Cass 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 Cass County, IA?
Cass County has a FEMA National Risk Index rating of Relatively Low, placing it in the 60th 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 Cass County?
Cass County is evaluated for five major natural hazard types: tornado (76th percentile), flooding (43th percentile), wildfire (41th percentile), hurricane (18th percentile), earthquake (16th percentile). The highest-risk hazard is tornado at the 76th 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 Cass County risk compare to the Iowa average?
Cass County's composite risk percentile is 60th, compared to the Iowa state average of 40th percentile. The state's overall risk rating is Very Low. This means Cass County faces higher natural disaster risk than the typical county in Iowa.
Is Cass County at risk for tornado?
Yes, Cass County's tornado risk is at the 76th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Cass County is at the 43th 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 Cass County higher risk than average?
Cass County's composite risk score of 60th percentile is above the Iowa state average of 40th percentile. This elevated risk is driven by tornado exposure (76th percentile). Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.
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.