Climate Risk Summary

Portsmouth, NH 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.

City-Wide Aggregation

These scores represent the population-weighted average across all residential blocks in Portsmouth.

Primary Risks

Inland Flooding

$3,206,745

Expected Annual Loss for Portsmouth

33.5Score

Relatively Moderate compared to US average

Portsmouth
Minimal Estimated LossMax Estimated Loss

Earthquake

$845,446

Expected Annual Loss for Portsmouth

72.1Score

Relatively Moderate compared to US average

Portsmouth
Minimal Estimated LossMax Estimated Loss

Coastal Flooding

$597,372

Expected Annual Loss for Portsmouth

75.0Score

Relatively High compared to US average

Portsmouth
Minimal Estimated LossMax Estimated Loss

City Boundary

Legend
Very Low
Low
Moderate
High
Very High
Extreme

Financial Risk Inventory

MAJOR DRIVER
Inland Flooding
$3,206,745
Score: 33.5
MAJOR DRIVER
Earthquake
$845,446
Score: 72.1
MAJOR DRIVER
Coastal Flooding
$597,372
Score: 75.0
Hurricane
$458,457
Score: 70.7
Tornado
$196,331
Score: 35.7
UNUSUALLY HIGH
Ice Storm
$160,810
Score: 82.2
Cold Wave
$121,800
Score: 29.6
Strong Wind
$82,123
Score: 39.5
Lightning
$58,805
Score: 40.0
Heat Wave
$57,145
Score: 10.9
Hail
$12,529
Score: 28.1
Winter Weather
$11,108
Score: 39.5
Wildfire
$1,960
Score: 43.1
Landslide
$49
Score: 54.5

Recommended investments to protect your property value and reduce insurance liability based on your local risk profile.

🏠Low Investment

Earthquake Mitigation

General property maintenance and insurance review recommended.

Risk Score: 72.1
🏠Low Investment

Coastal Flooding Mitigation

General property maintenance and insurance review recommended.

Risk Score: 75.0
🌀High Investment

Hurricane Mitigation

Install permanent hurricane shutters or upgrade to impact-resistant windows.

Risk Score: 70.7
❄️Medium Investment

Ice Storm Mitigation

Install a 10kWh backup battery system to keep pipes from freezing during grid failure.

Risk Score: 82.2
⛰️High Investment

Landslide Mitigation

Professional slope stabilization and foundation drainage inspection is highly recommended.

Risk Score: 54.5

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

Nearby Cities

KitterySouth EliotYork HarborDoverDurham

Zip Codes in Portsmouth

03801