Yuma County, Arizona Natural Disaster Risk
FEMA National Risk Index assessment · AZ
MediumComposite Risk Score
National percentile: 93th
Yuma County faces medium composite natural disaster risk (NRI Risk Index score 92.6, 93th national percentile), driven primarily by earthquake and heat wave exposure. Expected annual loss across all 18 hazard types is $91M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Yuma County at medium composite risk, with a National Risk Index score of 92.6 out of 100 — placing it in the 93rd national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by earthquake (ground shaking from sudden movement along geologic faults) at High risk — $52M in expected annual loss and about 0.09 events per year; heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at High risk — $6M in expected annual loss and about 15.77 events per year; and riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at Medium risk — $32M in expected annual loss and about 1.32 events per year. Across all hazards, FEMA estimates $91M in expected annual loss for a population of 203K.
Beyond physical exposure, Yuma County has a high social vulnerability rating (how susceptible the population is to harm) and a very low community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
The federal record bears this out: Yuma County has received 6 federal disaster declarations since 1983, including 2 for biological events and 2 for flood events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 15 Arizona counties, Yuma County ranks #8 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Earthquake | High | 0.09 / yr | $52M |
| Heat Wave | High | 15.77 / yr | $6M |
| Riverine Flood | Medium | 1.32 / yr | $32M |
| Drought | Medium | 40.07 / yr | $513K |
| Strong Wind | Medium | 0.33 / yr | $562K |
| Volcanic Activity | Very Low | 0.00 / yr | $23 |
| Wildfire | Very Low | 0.00 / yr | $58K |
| Landslide | Very Low | 3.67 / yr | $762 |
| Lightning | Low | 19.69 / yr | $136K |
| Hurricane | Very Low | 0.02 / yr | $6K |
| Hail | Very Low | 0.04 / yr | $43K |
| Tornado | Very Low | 0.07 / yr | $91K |
| Winter Weather | Very Low | 0.00 / yr | $0 |
| Avalanche | Very Low | 0.00 / yr | $0 |
| 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 |
Disaster History
Yuma County has received 6 federal disaster declarations since 1983, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Biological (2), Flood (2), Hurricane (1).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| January 1993 | Flood | Severe Storms, Tornadoes & Flooding |
| January 1985 | Severe Storm | Heavy Rain & High Winds |
| July 1983 | Flood | Flooding |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Yuma County?
Yuma County has a composite FEMA National Risk Index score of 92.6 out of 100, placing it in the Medium category and the 93th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Yuma County?
The three highest-rated hazards are Earthquake (High, $52M EAL), Heat Wave (High, $6M EAL), Riverine Flood (Medium, $32M EAL). These account for most of the county's expected annual losses.
How does Yuma County compare to other Arizona counties?
Yuma County ranks #8 of 15 Arizona counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Yuma County had?
FEMA records 6 federal disaster declarations for Yuma County since 1983, most often 2 for biological events and 2 for flood events. The most recent was Covid-19 Pandemic, declared in April 2020.
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. Yuma County's $91M EAL is a statistical average, not a guarantee for any specific year or address.