Portsmouth, NH Flooding & Climate Risk Profile
The primary drivers of climate-related financial risk in Portsmouth, NH are Inland Flooding, Earthquake, and Coastal Flooding. This area also faces an unusually high intensity for Ice Storm compared to national averages. Based on recent federal data, homeowners in this market face an estimated average annual insurance premium of $1,518, with a local policy non-renewal rate of 0.7%.
Based on FEMA EAL and hazard intensity.
Metrics indicate a balanced risk-to-premium environment with standard renewal rates.
Spatial Analysis
Flood Plain Analysis
Localized Flood Dynamics in Portsmouth
FEMA Flood Maps for Portsmouth 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 & Climate Stress Analysis
Current Avg. Premium (2022)
Recent Year Change
2030 Forecast
Market Retreat (Non-Renewals)
Higher rates indicate insurers are actively reducing exposure to Portsmouth due to climate-linked risk.
Underwriting Stress (Loss Ratio)
A ratio over 70% suggests insurers are paying out nearly all premiums as claims, forcing future price hikes.
Historical Market Trends
Toggle series below to compare costs vs. market stress indicators
Historical Trends & Forecasting
Compare premium costs against underlying risk factors.
Primary Risks
Inland Flooding
Expected Annual Loss for Portsmouth
Relatively Moderate compared to US average
Earthquake
Expected Annual Loss for Portsmouth
Relatively Moderate compared to US average
Coastal Flooding
Expected Annual Loss for Portsmouth
Relatively High compared to US average
Financial Risk Inventory
Recommended Mitigation Strategies
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.
Coastal Flooding Mitigation
General property maintenance and insurance review recommended.
Hurricane Mitigation
Install permanent hurricane shutters or upgrade to impact-resistant windows.
Ice Storm Mitigation
Install a 10kWh backup battery system to keep pipes from freezing during grid failure.
Landslide Mitigation
Professional slope stabilization and foundation drainage inspection is highly recommended.
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.