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

St. Louis County Disaster Risk

St. Louis County, Missouri

FEMA Risk Rating

Relatively High

National Percentile

99th

of 3,144 counties

State Rank

#1

of 115 (1 = highest risk)

Flood Risk

99th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively High

Higher than 99% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 62% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively High

Higher than 98% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 99% of US counties

Hurricane

Tropical cyclone and hurricane risk

Relatively Low

Higher than 45% of US counties

Risk Overview

About Natural Disaster Risk in St. Louis County, Missouri

St. Louis County: Nation's Highest-Risk Areas

St. Louis County's composite risk score of 99.33 rates as "Relatively High," placing it among America's most hazard-exposed counties. Nearly every resident faces significantly above-average natural disaster risk.

Missouri's Single Highest-Risk County

At 99.33, St. Louis County far exceeds Missouri's state average of 50.56, representing the state's most dangerous natural hazard environment. The county's risk profile is nearly twice the state mean.

Nearly Identical Risk to St. Louis City

St. Louis County (99.33) and St. Louis City (98.70) form a virtually unified high-risk metropolitan zone with minimal variation. Together they represent the most hazard-exposed region in Missouri by a substantial margin.

Four Major Hazards Converge Here

St. Louis County residents face severe tornado risk (98.06), catastrophic flood danger (99.08), significant earthquake exposure (99.05), and notable hurricane risk (45.10). This unprecedented convergence of multiple major hazards requires sophisticated disaster planning.

Comprehensive Coverage Absolutely Essential

St. Louis County homeowners must secure flood, tornado, and earthquake insurance without exception—all three hazards pose serious threats. Additional investments in storm-resistant upgrades and flood mitigation could save lives and property.

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

Preparedness Guide

What to Prepare for in St. Louis County

Top Hazards by Exposure

  1. #1
    FloodPrepare
    99th percentile
  2. #2
    EarthquakePrepare
    99th percentile
  3. #3
    TornadoPrepare
    98th percentile

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

Risk Advisory: St. Louis County

Risk Verdict

Natural hazard exposure in St. Louis County is notably high, placing it at the 99th percentile among all U.S. counties. St. Louis County's elevated composite score reflects cumulative multi-hazard exposure; households should prepare for the county's two or three primary hazard types.

Hazard Breakdown

Flood risk is St. Louis County's dominant natural hazard, ranked at the 99th percentile nationally under FEMA's National Risk Index. Earthquake ranks second at the 99th percentile nationally. Additional tracked hazards include tornado (98th percentile), wildfire (62th percentile), hurricane (45th percentile).

Preparedness Context

With flood ranked as the primary hazard at the 99th percentile nationally, St. Louis County households should build a go-bag that includes important documents, medications, and supplies to sustain the family for at least three days if evacuation is needed. Secondary earthquake exposure at the 99th percentile adds a second preparedness layer; households should review coverage options and alert sign-up for both hazard types. A waterproof container for documents (insurance policies, ID, prescriptions) and a clear household communication plan for when phone networks are congested are the two highest-value low-cost preparedness steps for St. Louis County households.

Regional Context

A composite score 48.8 points above the Missouri state average puts St. Louis County in a higher-risk category than most counties in the state.

Is your household prepared for St. Louis 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. Louis County, MO?
St. Louis County has a FEMA National Risk Index rating of Relatively High, placing it in the 99th 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. Louis County?
St. Louis County is evaluated for five major natural hazard types: flooding (99th percentile), earthquake (99th percentile), tornado (98th percentile), wildfire (62th percentile), hurricane (45th percentile). The highest-risk hazard is flooding at the 99th 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. Louis County risk compare to the Missouri average?
St. Louis County's composite risk percentile is 99th, compared to the Missouri state average of 51th percentile. The state's overall risk rating is Relatively Low. This means St. Louis County faces higher natural disaster risk than the typical county in Missouri.
Is St. Louis County at risk for flooding?
Yes, St. Louis County's flooding risk is at the 99th percentile nationally. This places it in the top quartile for this hazard type.
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. Louis County higher risk than average?
St. Louis County's composite risk score of 99th percentile is above the Missouri state average of 51th percentile. This elevated risk is driven by flooding exposure (99th percentile), along with earthquake and tornado and wildfire risk. 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.