Primary Data Sources

This application integrates data from multiple authoritative sources to provide comprehensive disaster risk and impact analysis:

NOAA NCEI Billion-Dollar Disasters

The primary dataset for billion-dollar weather and climate disasters, maintained by NOAA's National Centers for Environmental Information.

Visit NCEI Billions →

FEMA National Risk Index (NRI)

County-level natural hazard risk assessments including Expected Annual Loss, Social Vulnerability, and Community Resilience scores.

Visit FEMA NRI →

CDC Social Vulnerability Index

Census tract-level social vulnerability data used to assess community resilience to disasters.

Visit CDC SVI →

U.S. Census Bureau

Population data, American Community Survey statistics, and geographic boundaries used throughout the application.

Visit Census Bureau →

Cost Estimation Methodology

The billion-dollar disaster cost estimates are developed using a rigorous methodology established by NOAA's National Centers for Environmental Information:

1

Data Collection

Costs are compiled from multiple sources including insurance industry data, government agencies (FEMA, USDA, SBA), reinsurance companies, and academic research.

2

Damage Categories

Estimates include physical damage to residential, commercial, and government buildings; infrastructure and vehicles; agricultural assets including crops, livestock, and timber; and disaster restoration costs.

3

Conservative Estimates

Costs represent conservative estimates that do not include losses to natural capital, health care, or supply chain disruption. Actual costs are likely higher than reported.

4

CPI Adjustment

Historical costs can be adjusted for inflation using the Consumer Price Index (CPI) to enable meaningful comparison of disaster costs across different years.

Important Note on Cost Estimates

The $1 billion threshold is based on the original 1980 dollar value and is not adjusted over time. This means that with inflation, it has become easier for events to exceed this threshold, which partially explains the increase in billion-dollar events in recent decades.

Risk Assessment Methodology

FEMA National Risk Index

The Risk Map feature uses FEMA's National Risk Index, which quantifies risk as a function of:

  • Expected Annual Loss (EAL): The average economic loss expected each year from natural hazards
  • Social Vulnerability: The susceptibility of social groups to adverse impacts from natural hazards
  • Community Resilience: The ability of a community to prepare for, adapt to, and recover from natural hazards

Risk Calculation

The overall risk score is calculated as:

Risk = Expected Annual Loss × Social Vulnerability ÷ Community Resilience

Risk scores are normalized on a 0-100 scale, with higher scores indicating greater risk. The index covers 18 natural hazard types and provides data at the county and census tract level.

Data Processing & Updates

Data Refresh Schedule

  • Disaster Events: Updated as new billion-dollar events are confirmed by NOAA NCEI
  • Cost Estimates: Refined as additional loss information becomes available, typically within 6-12 months after an event
  • Risk Index Data: Updated annually by FEMA with latest census and hazard data
  • Social Vulnerability: Updated every 2-4 years based on American Community Survey releases

Data Quality Assurance

All data undergoes quality control processes including:

  • Validation against official source publications
  • Cross-referencing between multiple data sources
  • Automated consistency checks during data loading
  • Manual review of outliers and anomalies

Peer-Reviewed Literature

The methodology and data used in this application are grounded in peer-reviewed scientific research:

Technical Reports & Annual Analyses

Additional Resources

NOAA Billion-Dollar Disasters FAQ

Frequently asked questions about disaster costs and methodology from NOAA.

View FAQ →

Climate Central BDD

Interactive tools and analyses of billion-dollar disasters from Climate Central.

Visit Climate Central →

NOAA Climate.gov

Climate science information and data from NOAA's Climate Program Office.

Visit Climate.gov →

CDC SVI Documentation

Technical documentation for the Social Vulnerability Index methodology.

View Documentation →

Disclaimer

This application is provided for informational and educational purposes. While we strive for accuracy, the data and analyses presented here should not be used as the sole basis for decision-making. Users should consult original data sources and professional expertise for critical applications.

Cost estimates are subject to revision as additional information becomes available. Historical event details may be refined over time as post-event assessments are completed.

For the most current and authoritative data, please visit the official NOAA NCEI Billion-Dollar Weather and Climate Disasters page.