riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Mariposa County Disaster Risk

Mariposa County, California

FEMA Risk Rating

Relatively Moderate

National Percentile

86th

of 3,144 counties

State Rank

#43

of 58 (1 = highest risk)

Flood Risk

71th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 71% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively High

Higher than 99% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 6% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 67% of US counties

Risk Overview

About Natural Disaster Risk in Mariposa County, California

Mariposa's moderate composite risk

Mariposa County scores 86.4 on the composite risk scale, earning a "Relatively Moderate" rating slightly below California's state average of 88.7. The small Sierra Nevada county faces manageable but real natural disaster exposure.

Mid-tier risk among California counties

Mariposa County ranks in the middle of California's 58 counties for composite disaster risk, neither among the highest nor lowest-risk communities. Its 86.4 score reflects moderate but meaningful hazard exposure.

Safer than surrounding mountain counties

Mariposa County's 86.4 risk score is considerably lower than neighboring Madera County (96.4) and other nearby mountain communities, making it one of the region's safer areas. Lower earthquake and flood risks distinguish it from adjacent counties.

Wildfire is the dominant hazard

Mariposa County's greatest natural disaster risk comes from wildfire, which scores 99.0 out of 100 and represents the county's primary concern. Earthquake (67.5) and flood (70.8) risks are notably lower than in neighboring counties.

Wildfire insurance is essential

Mariposa County residents should prioritize dedicated wildfire insurance and maintain defensible space around their homes. Standard earthquake coverage is advisable but represents a secondary concern relative to the county's extreme wildfire exposure.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Mariposa County

Top Hazards by Exposure

  1. #1
    WildfirePrepare
    99th percentile
  2. #2
    FloodPrepare
    71th percentile
  3. #3
    EarthquakePrepare
    67th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Mariposa County

Risk Verdict

Mariposa County's overall risk score at the 86th percentile nationally signals meaningful exposure to multiple natural hazard types. Comprehensive household preparedness — including reviewing insurance, maintaining emergency supplies, and knowing evacuation routes — is strongly recommended.

Hazard Breakdown

Wildfire risk is Mariposa County's dominant natural hazard, ranked at the 99th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 71th percentile nationally. Additional tracked hazards include earthquake (67th percentile), tornado (6th percentile).

Preparedness Context

Mariposa County's dominant hazard is wildfire, ranked at the 99th percentile nationally. Maintaining at least 30 feet of lean, clean vegetation around structures in Mariposa County and keeping gutters clear of debris significantly reduces ignition risk from wind-driven embers. The county's flood exposure at the 71th percentile nationally complements the wildfire risk — saturating rain after burn scarring often triggers secondary flood and debris flow events. Mariposa County's households benefit from reviewing homeowners insurance before fire season, specifically whether the policy covers replacement cost rather than actual cash value, and whether it includes additional living expenses if displacement is required.

Regional Context

The county's composite score diverges by only 2.3 points from the California average, making Mariposa County's hazard profile broadly typical for this part of the state.

Is your household prepared for Mariposa County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Mariposa County, CA?
Mariposa County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 86th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Mariposa County?
Mariposa County is evaluated for five major natural hazard types: wildfire (99th percentile), flooding (71th percentile), earthquake (67th percentile), tornado (6th percentile). The highest-risk hazard is wildfire at the 99th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Mariposa County risk compare to the California average?
Mariposa County's composite risk percentile is 86th, compared to the California state average of 89th percentile. The state's overall risk rating is Relatively Moderate. This means Mariposa County faces lower natural disaster risk than the typical county in California.
Is Mariposa County at risk for wildfire?
Yes, Mariposa County's wildfire risk is at the 99th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Mariposa County is at the 71th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Is Mariposa County a safe place to live?
Mariposa County's composite risk score of 86th percentile is below the California state average of 89th percentile, indicating relatively lower exposure to natural hazards. However, no county is completely risk-free. The primary hazard type is wildfire at the 99th percentile. Residents should still maintain emergency preparedness plans and appropriate insurance coverage.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.