Climate Risk Summary
Alton, IL Risk Profile
The primary drivers of climate-related financial risk in Alton, IL are Inland Flooding, Earthquake, and Tornado. This area also faces an unusually high intensity for Heat Wave, Hail, and Landslide compared to national averages.
City-Wide Aggregation
These scores represent the population-weighted average across all residential blocks in Alton.
Primary Risks
Inland Flooding
Expected Annual Loss for Alton
Relatively High compared to US average
Earthquake
Expected Annual Loss for Alton
Relatively High compared to US average
Tornado
Expected Annual Loss for Alton
Relatively High compared to US average
City Boundary
Financial Risk Inventory
Recommended investments to protect your property value and reduce insurance liability based on your local risk profile.
Earthquake Mitigation
General property maintenance and insurance review recommended.
Tornado Mitigation
Reinforce garage doors and consider a FEMA-approved safe room or storm cellar.
Heat Wave Mitigation
Ensure attic insulation is R-49+ and consider a dual-fuel backup generator for AC.
Cold Wave Mitigation
General property maintenance and insurance review recommended.
Hail Mitigation
Replace roof with Class 4 impact-resistant shingles to significantly lower insurance premiums.
Lightning Mitigation
General property maintenance and insurance review recommended.
Winter Weather Mitigation
General property maintenance and insurance review recommended.
Landslide Mitigation
Professional slope stabilization and foundation drainage inspection is highly recommended.
Sources and Methodology
Spatial Aggregation
Our "Atlas" risk scores are derived using a population-weighted spatial join. Because US Zip Codes and Census Tracts do not share perfectly aligned boundaries, a simple geographic average would be misleading. We utilize US Census Block Group population statistics to identify where residents actually live within a Zip Code. We then intersect these points with FEMA National Risk Index (NRI) hazard data to calculate a weighted exposure score.
Financial Projections (EAL)
Expected Annual Loss (EAL) estimates the average economic impact of natural hazards in dollars per year. This calculation incorporates three components: Exposure (the value of structures and agriculture), Annualized Frequency (historical probability), and Historic Loss Ratio (vulnerability of the area).
Primary Data Sources
- FEMA National Risk IndexHazard frequency and loss data (v1.20.0)
- U.S. Census BureauTIGER/Line 2025 Shapefiles & Decennial Population