GeraSure / County Hazard Risk / Napa, CA
Napa County, California: Natural Hazard Risk
Gera County Hazard Score: 72/100 (High) · FEMA Rating: Relatively High · Population: 137,956. Based on FEMA National Risk Index (November 2023).
What is the natural hazard risk for Napa County, California?
Napa County, California has a Gera County Hazard Score (GCHS) of 72/100 (High), based on FEMA National Risk Index November 2023 data. Its Expected Annual Loss rank is 97.9/100, social vulnerability rank 62.1/100 and community resilience rank 78/100, covering a population of 137,956.
GCHS components — Napa County (November 2023)
| Component | Score / 100 | GCHS Weight | Contribution | What it measures |
|---|---|---|---|---|
| Expected Annual Loss (EAL) | 97.9 | 50% | 49.0 | Estimated annual losses from 18 natural hazards |
| Social Vulnerability (SOVI) | 62.1 | 30% | 18.6 | Community factors affecting disaster response capacity |
| Lack of Resilience (100 − RESL) | 22 | 20% | 4.4 | Resilience score 78/100 → inverted so higher = more hazard |
| Gera County Hazard Score (GCHS) | 72 | 100% | 72 | High — composite index |
GCHS = 0.50 × 97.9 + 0.30 × 62.1 + 0.20 × (100 − 78) = 72.0. All inputs are FEMA NRI percentile ranks 0–100.
Napa County Hazard Checker
Explore what the GCHS means for insurance and disaster preparedness in this county.
Gera County Hazard Score (GCHS)
What this means for insurance
Counties rated High on the GCHS often carry above-average insurance costs for hazard-exposed properties. Multi-peril coverage gaps are common.
GCHS is computed by Gera from FEMA NRI data. It is a risk-context index — not an insurance premium quote. Actual premiums depend on your specific property and chosen coverage.
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Napa County hazard risk: frequently asked questions
- What does a GCHS of 72/100 mean for Napa County?
- A GCHS of 72/100 places Napa County in the "High" band. This is an above-average risk rating. The county's Expected Annual Loss rank (97.9/100) and Social Vulnerability (62.1/100) are primary risk contributors.
- Which natural hazards most affect Napa County?
- The GCHS is computed from FEMA's Expected Annual Loss (EAL) score, which aggregates 18 natural hazard types: hurricanes, riverine flooding, tornadoes, wildfires, earthquakes, hail, drought, winter weather, lightning, strong wind, coastal flooding, cold wave, heat wave, ice storm, landslide, avalanche, tsunami and volcanic activity. Napa County's EAL rank is 97.9/100 — very high, suggesting substantial exposure to one or more of these hazards.
- What is the FEMA National Risk Index?
- The FEMA National Risk Index (NRI) is a publicly available dataset produced by the US Federal Emergency Management Agency that measures the risk of natural hazards for every US county and census tract. It combines 18 natural hazard types, community social vulnerability and community resilience into a single expected-loss-based risk score. Gera computes the GCHS from the NRI's county-level EAL, SOVI and RESL percentile scores using a documented formula.
- How does Napa County compare to the national average?
- The national mean GCHS across the 480 most-populous US counties is 66.1/100. Napa County scores 72/100, which is 5.9 points above the national mean. FEMA's own risk rating for this county is "Relatively High".
Other CA counties
All counties →Contains public sector information published by Federal Emergency Management Agency (FEMA) and licensed under the US Government open data, public domain. Source: FEMA National Risk Index (NRI) — Harvard Dataverse (November 2023, published 2024).
Full GCHS formula and verification: Gera County Hazard Score methodology.