Climate Risk Summary
Zip Code 21520, Risk Profile
The primary drivers of climate-related financial risk in Unincorporated, MD (21520) are Inland Flooding, Hurricane, and Cold Wave. This area also faces an unusually high intensity for Hail, Winter Weather, Drought, and Landslide compared to national averages.
Understanding the Dollars
Expected Annual Loss (EAL) is a statistical average of property damage for this entire zip code over a standard year across all properties.
- / It represents the "average cost" rather than a guaranteed yearly bill.
- / It can be used to compare the relative risk from different hazards and across different neighborhoods.
Primary Risks
Inland Flooding
Expected Annual Loss for Zip Code 21520
Relatively Moderate compared to US average
Hurricane
Expected Annual Loss for Zip Code 21520
Relatively Low compared to US average
Cold Wave
Expected Annual Loss for Zip Code 21520
Relatively Moderate compared to US average
Zip Code Risk Map
Financial Risk Inventory
Recommended Mitigation Strategies
Recommended investments to protect your property value and reduce insurance liability based on your local risk profile.
Inland Flooding Mitigation
Install a smart sump pump with battery backup and extend downspouts 10ft from foundation.
Hurricane Mitigation
Install permanent hurricane shutters or upgrade to impact-resistant windows.
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.
Winter Weather Mitigation
General property maintenance and insurance review recommended.
Drought Mitigation
General property maintenance and insurance review recommended.
Landslide Mitigation
Professional slope stabilization and foundation drainage inspection is highly recommended.
Methodology and Sources
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 - Dec 2025)
- U.S. Census BureauTIGER/Line 2025 Shapefiles & Decennial Population