Johnston, IA
Local storm history & FEMA National Risk Index data
Johnston is rated Relatively Moderate for overall natural hazard risk — near the middle compared to other US counties — based on FEMA's National Risk Index for Polk County, IA. The county's highest-rated hazards are strong wind, tornado, and hail.
Storm events near Johnston
NOAA-recorded tornado, hail, and flood events within 25 miles of Johnston's center, 2016–2026 — the only hazards NOAA reports with exact coordinates, so these counts are specific to Johnston itself, not the whole county.
County-wide hazard risk
Every other hazard FEMA and NOAA track — including drought — is only scored at the county level. These are Polk County's FEMA National Risk Index scores, covering Johnston along with the rest of the county, not a Johnston-specific figure.
| Hazard | NRI score | Rating |
|---|---|---|
| Wildfire | 57.7 | Very Low |
| Inland Flooding | 92.1 | Relatively Moderate |
| Coastal Flooding | — | Not Applicable |
| Earthquake | 66.8 | Relatively Low |
| Heat Wave | 96.7 | Relatively High |
| Tornado | 98.1 | Relatively High |
| Avalanche | — | Not Applicable |
| Cold Wave | 91.3 | Relatively High |
| Drought | 94.8 | Relatively High |
| Hail | 97.9 | Relatively High |
| Hurricane | 27.5 | Very Low |
| Ice Storm | 91.7 | Relatively High |
| Landslide | 68.4 | Relatively Low |
| Lightning | 78.1 | Relatively Moderate |
| Strong Wind | 99.2 | Very High |
| Tsunami | — | Not Applicable |
| Volcanic Activity | — | Not Applicable |
| Winter Weather | 90.3 | Relatively High |
Source: FEMA National Risk Index v1.20.0, December 2025. See the methodology page for definitions, or the full Polk County risk profile for disaster declarations, social vulnerability, and climate projection data.
Other cities in Polk County:
More on Polk County:
Frequently asked questions
What natural hazards is Johnston, IA at risk of?
Johnston is rated Relatively Moderate for overall natural hazard risk by FEMA's National Risk Index — near the middle compared to other US counties. The highest-rated hazards for Polk County, where Johnston is located, are strong wind, tornado, and hail.
What is Johnston's biggest natural hazard risk?
Strong Wind is the highest-rated hazard for Polk County, where Johnston is located, scoring 99.2 out of 100 on FEMA's National Risk Index (rated "Very High").
Is Johnston a high-risk area for natural disasters?
Somewhat — Johnston carries near the middle compared to other US counties for overall natural hazard risk, per FEMA's National Risk Index rating of "Relatively Moderate" for Polk County.
Has Johnston had tornadoes, hail, or flooding?
NOAA has recorded 48 tornado, 337 hail, 149 inland flooding events within 25 miles of Johnston since 2016.