// Overview
Every county in the ThreatMap USA database is assigned a Threat Score from 1 to 10 and a corresponding risk level: Low, Moderate, High, or Critical.
The score is a composite index that weighs five primary factors: federally declared disaster history, primary hazard type and severity, FEMA flood zone classification, historical event frequency, and population exposure. No single factor determines the score — a county with frequent minor events may score lower than a county with fewer but catastrophic ones.
Scores are intended to reflect relative risk within the United States, not absolute safety guarantees. A score of 3 (Low) does not mean a county is immune to disaster — it means its historical and geographic risk profile is significantly lower than the national average.
// The Five Scoring Factors
FEMA Disaster Declaration Count
We pull the total number of federally declared major disasters for each county from FEMA's publicly available disaster declarations database. Counties with 50+ declarations receive maximum weight on this factor. This data reflects decades of real disaster history — not projections or models.
Primary Hazard Type & Severity
Not all hazards are equal. We classify each county's primary hazard and weight it by its potential for mass casualties, infrastructure destruction, and displacement. Storm surge and earthquake carry the highest severity multipliers. Severe thunderstorms and drought carry lower multipliers. A county's score reflects what its worst-case scenario actually looks like.
| Hurricane / Storm Surge | Severity: Critical |
| Earthquake | Severity: Critical |
| Wildfire (Urban Interface) | Severity: High |
| Tornado / Severe Storm | Severity: High |
| Flash Flooding | Severity: Moderate–High |
| Extreme Heat | Severity: Moderate |
| Drought / Winter Storm | Severity: Low–Moderate |
FEMA Flood Zone Classification
FEMA's National Flood Insurance Program (NFIP) classifies land into flood zones based on inundation risk. Zone VE (coastal high hazard) and Zone AE (1% annual flood chance) contribute positively to a county's score. Zone X (minimal risk) contributes less. For coastal counties, storm surge zones carry additional weight.
Historical Event Frequency
We calculate how often a county experiences a significant disaster event based on its FEMA declaration history relative to the number of years on record. A county that experiences a major event every 2–3 years scores higher on this factor than one with a major event every decade. Frequency compounds risk — residents have less time to recover between events.
Population Exposure
A disaster affecting 4 million people is categorically different from one affecting 40,000. We factor population into the score as a modifier — large urban counties in high-risk zones receive a score boost reflecting the scale of potential impact. This is why Harris County (4.7M residents) scores 9/10 while a rural coastal county with similar hazards might score 7/10.
// Risk Level Scale
Threat Scores map to four risk levels. The color system used across the site reflects these tiers — green for low, yellow for moderate, orange for high, red for critical.
// Data Sources
ThreatMap USA draws from the following publicly available government datasets:
| FEMA Disaster Declarations | openfema.gov |
| FEMA Flood Zone Maps | msc.fema.gov |
| Population & Demographics | US Census Bureau ACS |
| National Weather Service Hazard Data | weather.gov |
| USGS Earthquake Hazard Program | earthquake.usgs.gov |
| USFS Fire Occurrence Data | fs.usda.gov |
// Limitations & Disclaimer
ThreatMap USA scores are intended for general informational and educational purposes only. They are not a substitute for official emergency guidance from FEMA, your state emergency management agency, or local authorities.
Scores reflect historical data and known geographic risk factors. They cannot predict future disasters. Conditions change — a county's risk profile may shift due to new development, climate trends, infrastructure changes, or updated FEMA flood maps. We review and update county data periodically.
In an emergency, always follow instructions from official authorities. Contact your county emergency management office or call 911.
// Update Schedule
| FEMA Disaster Count | Updated annually or after major new declarations |
| Threat Scores | Reviewed annually and after catastrophic events |
| Population Data | Updated with each US Census ACS release |
| Affiliate Links | Reviewed quarterly for product availability |
| Incident Feed | Updated as events occur |
// Start Exploring