Climate Risk Summary
Somerville, MA Risk Profile
The primary drivers of climate-related financial risk in Somerville, MA are Inland Flooding, Hurricane, and Earthquake. Based on recent federal data, homeowners in this market face an estimated average annual insurance premium of $2,252, with a local policy non-renewal rate of 1.5%.
Based on FEMA EAL and hazard intensity.
Metrics indicate a balanced risk-to-premium environment with standard renewal rates.
Primary Risks
Inland Flooding
Expected Annual Loss for Somerville
Relatively Low compared to US average
Hurricane
Expected Annual Loss for Somerville
Relatively Moderate compared to US average
Earthquake
Expected Annual Loss for Somerville
Relatively Moderate compared to US average
Spatial Analysis
Flood Plain Analysis
Localized Flood Dynamics in Somerville
FEMA Flood Maps for Somerville identify the "100-year" and "500-year" floodplains (1% and 0.2% annual chance), but modern climate risk analysis suggests that nearly 25% of flood insurance claims originate from properties outside of these designated high-risk zones.
Insurance Market Stability
Avg. Annual Premium
Estimated baseline property insurance cost prior to localized disaster surcharges.
Non-Renewal Rate
The percentage of homeowner policies canceled by insurers, a key indicator of market retreat.
Insurer Loss Ratio
For every $1 collected in premium, insurers are paying out $0.20 in claims.
Financial Risk Inventory
Recommended Mitigation Strategies
Recommended investments to protect your property value and reduce insurance liability based on your local risk profile.
Hurricane Mitigation
Install permanent hurricane shutters or upgrade to impact-resistant windows.
Sources and Methodology
Spatial Climate Risk Modeling
The Expected Annual Loss (EAL) and hazard risk scores are derived from the FEMA NRI zip code dataset using a population-weighted spatial join. Because Zip Codes and Census Tracts do not share perfectly aligned boundaries, we utilize US Census Block Group population centroids to identify where residents actually live.
Financial & Insurance Metrics
The pysical resilence score is calculated by synthesizing Expected Annual Loss (EAL) against the total building replacement value within a jurisdiction. This creates a "Loss Ratio" that measures physical resilience. We supplement this with ZIP-code level data from the U.S. Treasury's Federal Insurance Office (FIO), monitoring trends in premium growth, loss ratios, and policy non-renewals to identify emerging "Insurance Deserts."
Primary Data Sources
- FEMA National Flood Hazard LayerHigh-resolution vector data for 100-year and 500-year flood zones.
- U.S. Department of the TreasuryFIO ZIP-code level insurance data (2018–2022 Historical Set).
- FEMA National Risk IndexBaseline hazard frequency and economic loss data (v1.20.0).
- U.S. Census BureauTIGER/Line 2025 Shapefiles & Decennial Population Statistics.