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

St. Charles County Disaster Risk

St. Charles County, Missouri

FEMA Risk Rating

Relatively Moderate

National Percentile

93th

of 3,144 counties

State Rank

#4

of 115 (1 = highest risk)

Flood Risk

94th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Moderate

Higher than 94% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 59% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively High

Higher than 96% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 95% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 23% of US counties

Risk Overview

About Natural Disaster Risk in St. Charles County, Missouri

St. Charles County: Moderately Higher Risk

St. Charles County's composite risk score of 92.59 earns a "Relatively Moderate" rating, nearly double Missouri's state average of 50.56. This reflects significant exposure to multiple natural disaster hazards.

Among State's Highest-Risk Counties

St. Charles County ranks among Missouri's most hazard-prone areas, with its 92.59 composite score exceeding the state average substantially. Only a handful of Missouri counties face comparable overall disaster risk.

Riskier Than Most Regional Peers

St. Charles County (92.59) faces significantly higher risk than Shelby County (15.94) and St. Clair County (25.64) in the same region. Its risk profile aligns most closely with other major Missouri urban centers.

Tornadoes, Floods, and Earthquakes Dominate

St. Charles County confronts severe tornado risk (96.37), significant flood danger (94.24), and substantial earthquake exposure (94.62). Combined, these three hazards create a complex disaster environment requiring comprehensive preparedness.

Comprehensive Coverage Essential Here

St. Charles County residents should prioritize flood insurance, tornado-resistant construction standards, and comprehensive homeowners coverage. Given the county's elevated multi-hazard risk, additional protections could prove invaluable.

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

Preparedness Guide

What to Prepare for in St. Charles County

Top Hazards by Exposure

  1. #1
    TornadoPrepare
    96th percentile
  2. #2
    EarthquakePrepare
    95th percentile
  3. #3
    FloodPrepare
    94th percentile

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

Local Resources

Risk Advisory: St. Charles County

Risk Verdict

St. Charles County faces a moderate natural disaster risk profile, ranking at the 93th percentile nationally under FEMA's composite risk model. This risk level calls for more than general awareness: insurance coverage review, a family communication plan, and a prepared go-bag are practical priorities.

Hazard Breakdown

Tornado risk is St. Charles County's dominant natural hazard, ranked at the 96th percentile nationally under FEMA's National Risk Index. Earthquake ranks second at the 95th percentile nationally. Additional tracked hazards include flood (94th percentile), wildfire (59th percentile), hurricane (23th percentile).

Preparedness Context

Tornado risk is St. Charles County's top-ranked natural hazard at the 96th percentile nationally. For St. Charles County households, the most protective action available is identifying a reinforced interior room on the lowest floor — a bathroom, closet, or central hallway away from windows. Earthquake is the second hazard driver for St. Charles County at the 95th percentile nationally, meaning households should maintain awareness of both severe-weather and earthquake-specific warning systems. A battery-powered NOAA All Hazards weather radio with an auto-alert tone is the highest-leverage single item for tornado preparedness in St. Charles County, since it delivers warnings even when power is out and phone networks are congested.

Regional Context

St. Charles County's composite risk score sits 42.0 points above the Missouri county average, placing it among the more hazard-exposed counties in the state.

Is your household prepared for St. Charles 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 St. Charles County, MO?
St. Charles County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 93th 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 St. Charles County?
St. Charles County is evaluated for five major natural hazard types: tornado (96th percentile), earthquake (95th percentile), flooding (94th percentile), wildfire (59th percentile), hurricane (23th percentile). The highest-risk hazard is tornado at the 96th 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 St. Charles County risk compare to the Missouri average?
St. Charles County's composite risk percentile is 93th, compared to the Missouri state average of 51th percentile. The state's overall risk rating is Relatively Low. This means St. Charles County faces higher natural disaster risk than the typical county in Missouri.
Is St. Charles County at risk for tornado?
Yes, St. Charles County's tornado risk is at the 96th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, St. Charles County is at the 94th 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 St. Charles County higher risk than average?
St. Charles County's composite risk score of 93th percentile is above the Missouri state average of 51th percentile. This elevated risk is driven by tornado exposure (96th percentile), along with earthquake and flooding and wildfire 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

Jefferson County

Missouri

-2.1

Relatively Moderate

91th percentile

Greene County

Missouri

-2.5

Relatively Moderate

90th percentile

Clay County

Missouri

-2.8

Relatively Moderate

90th 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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