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

Maricopa County Disaster Risk

Maricopa County, Arizona

FEMA Risk Rating

Very High

National Percentile

100th

of 3,144 counties

State Rank

#1

of 15 (1 = highest risk)

Flood Risk

100th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very High

Higher than 100% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very High

Higher than 100% of US counties

Tornado

Tornado and severe thunderstorm risk

Moderate

Higher than 84% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 97% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 27% of US counties

Risk Overview

About Natural Disaster Risk in Maricopa County, Arizona

Maricopa County faces extreme risks

Maricopa County scores 99.87 on the composite risk scale, earning a "Very High" rating and sitting far above Arizona's state average of 84.45. The state's most populous and hazard-exposed county faces nearly maximum composite risk across multiple disaster types.

Arizona's highest-risk county by far

Maricopa County ranks as Arizona's most hazard-exposed county, with a composite score that dwarfs all peers. Its 99.87 rating reflects extreme exposure to floods, wildfires, tornadoes, and earthquakes in a densely populated region.

Dramatically riskier than surrounding areas

Maricopa County's 99.87 score vastly exceeds La Paz County (83.52) to the west and Gila County (90.17) to the north. Its extreme rating is unmatched in the state, reflecting the convergence of urban density and multiple overlapping hazards.

Multiple severe hazards converge here

Maricopa County faces near-maximum flood risk (99.87), extreme wildfire exposure (99.62), and exceptionally high tornado (84.00) and earthquake risk (96.82). This unprecedented concentration of hazards makes it the state's most disaster-prone county.

Comprehensive coverage is non-negotiable

Maricopa County residents must secure wildfire and flood insurance beyond standard homeowners policies, given both score above 99. Earthquake and tornado coverage should also be evaluated, particularly for properties in areas with older construction.

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

Preparedness Guide

What to Prepare for in Maricopa County

Top Hazards by Exposure

  1. #1
    FloodPrepare
    100th percentile
  2. #2
    WildfirePrepare
    100th percentile
  3. #3
    EarthquakePrepare
    97th percentile

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

Risk Advisory: Maricopa County

Risk Verdict

FEMA's composite risk model places Maricopa County at the 100th percentile nationally — one of the country's highest natural hazard exposure zones. Comprehensive household preparedness — including reviewing insurance, maintaining emergency supplies, and knowing evacuation routes — is strongly recommended.

Hazard Breakdown

Flood risk is Maricopa County's dominant natural hazard, ranked at the 100th percentile nationally under FEMA's National Risk Index. Wildfire ranks second at the 100th percentile nationally. Additional tracked hazards include earthquake (97th percentile), tornado (84th percentile), hurricane (27th percentile).

Preparedness Context

Maricopa County sits at the 100th percentile nationally for flood exposure. Knowing your property's flood zone designation — available at FEMA's Flood Map Service Center — is the first step toward understanding actual exposure and insurance options. Secondary wildfire exposure at the 100th percentile adds a second preparedness layer; households should review coverage options and alert sign-up for both hazard types. Regardless of specific hazard, Maricopa County households benefit from a practiced communication plan: a designated out-of-state contact and a pre-agreed evacuation destination established before the season's peak risk period.

Regional Context

Compared to other Arizona counties, Maricopa County runs 15.4 composite risk points higher than the state mean — reflecting above-average hazard concentration in this area.

Is your household prepared for Maricopa 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 Maricopa County, AZ?
Maricopa County has a FEMA National Risk Index rating of Very High, placing it in the 100th 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 Maricopa County?
Maricopa County is evaluated for five major natural hazard types: flooding (100th percentile), wildfire (100th percentile), earthquake (97th percentile), tornado (84th percentile), hurricane (27th percentile). The highest-risk hazard is flooding at the 100th 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 Maricopa County risk compare to the Arizona average?
Maricopa County's composite risk percentile is 100th, compared to the Arizona state average of 85th percentile. The state's overall risk rating is Relatively Moderate. This means Maricopa County faces higher natural disaster risk than the typical county in Arizona.
Is Maricopa County at risk for flooding?
Yes, Maricopa County's flooding risk is at the 100th percentile nationally. This places it in the top quartile for this hazard type.
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.
Why is Maricopa County higher risk than average?
Maricopa County's composite risk score of 100th percentile is above the Arizona state average of 85th percentile. This elevated risk is driven by flooding exposure (100th percentile), along with wildfire and earthquake and tornado risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.
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.