Arizona tornado risk
Maricopa County has the highest tornado risk in Arizona, scoring 84 out of 100 — rated "Relatively Moderate" by FEMA's National Risk Index. Recorded tornado events across Arizona have increased 52% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Maricopa County | 84 | Relatively Moderate | 13 |
| 2 | Pima County | 37.5 | Relatively Low | 9 |
| 3 | Pinal County | 37.1 | Relatively Low | 5 |
| 4 | Yavapai County | 32.7 | Relatively Low | 5 |
| 5 | Coconino County | 24.3 | Very Low | 10 |
| 6 | Yuma County | 14 | Very Low | 1 |
| 7 | Gila County | 13.4 | Very Low | 1 |
| 8 | Cochise County | 10.4 | Very Low | 3 |
| 9 | Santa Cruz County | 8.7 | Very Low | 0 |
| 10 | Navajo County | 8 | Very Low | 5 |
| 11 | La Paz County | 4.6 | Very Low | 1 |
| 12 | Apache County | 3.6 | Very Low | 3 |
| 13 | Mohave County | 3.3 | Very Low | 3 |
| 14 | Graham County | 2.7 | Very Low | 0 |
| 15 | Greenlee County | 1.2 | Very Low | 0 |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Tornado risk nationally:
Other hazard risks in Arizona:
Frequently asked questions
What is the highest tornado risk county in Arizona?
Maricopa County, AZ has the highest tornado risk in Arizona, with a FEMA National Risk Index score of 84 out of 100 (rated "Relatively Moderate").
What causes tornado risk in Arizona?
Tornado risk concentrates in the central and southern plains ("Tornado Alley") and the Southeast ("Dixie Alley"), where atmospheric conditions favor supercell thunderstorm development. The highest scores often belong to counties with significant mobile home and manufactured housing stock, which carries disproportionate tornado mortality risk.