Maricopa County
Arizona — Natural Disaster Risk Assessment
Very HighComposite Risk Score
National percentile: 100th
Maricopa County faces very high composite natural disaster risk (NRI Risk Index score 99.9, 100th national percentile), driven primarily by heat wave and riverine flood exposure. Expected annual loss across all 18 hazard types is $2.20B.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Heat Wave | Very High | 19.83 / yr | $958M |
| Riverine Flood | Very High | 8.46 / yr | $1.12B |
| Wildfire | High | 0.00 / yr | $42M |
| Hail | Very High | 0.28 / yr | $24M |
| Strong Wind | Very High | 1.40 / yr | $9M |
| Drought | High | 62.54 / yr | $5M |
| Earthquake | Medium | 0.01 / yr | $31M |
| Lightning | High | 32.26 / yr | $2M |
| Tornado | Medium | 0.57 / yr | $5M |
| Landslide | Low | 2.11 / yr | $28K |
| Winter Weather | Low | 0.57 / yr | $47K |
| Avalanche | Very Low | 0.01 / yr | $144 |
| Hurricane | Very Low | 0.01 / yr | $12K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Cold Wave | Very Low | 0.00 / yr | $0 |
| Ice Storm | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Frequently Asked Questions
What is the overall natural disaster risk for Maricopa County?
Maricopa County has a composite FEMA National Risk Index score of 99.9 out of 100, placing it in the Very High category and the 100th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Maricopa County?
The three highest-rated hazards are Heat Wave (Very High, $958M EAL), Riverine Flood (Very High, $1.12B EAL), Wildfire (High, $42M EAL). These account for most of the county's expected annual losses.
How does Maricopa County compare to other Arizona counties?
Maricopa County ranks #1 of 15 Arizona counties for overall natural disaster risk, with a very high rating.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Maricopa County's $2.20B EAL is a statistical average, not a guarantee for any specific year or address.