Johnson County, Iowa: hazard risk
FEMA rates Johnson County's overall risk Relatively Moderate (score 87.4 of 100, higher than 87% of rated U.S. counties); 5 of its 14 hazards are rated Relatively High or Very High, led by strong wind, tornado, hail. Its storm record holds 901 events since 1950.
FEMA's rating for each hazard
These are FEMA's county-wide model ratings and this county's storm record. They are not an assessment of any property, address or building, and not insurance advice: a property's risk depends on its own elevation, construction and location.
FEMA gives each hazard its own rating, and a rating does not follow the score from one hazard to the next: a hazard with a higher score can carry a lower rating than another. The table sorts by FEMA's rating, then by score (0 to 100, the county against every other county for that hazard).
| Hazard | Risk rating | Score | Expected annual loss |
|---|---|---|---|
| Strong Wind | Very High | 98.9 | $10M |
| Tornado | Relatively High | 98.2 | $36M |
| Hail | Relatively High | 95.3 | $4.4M |
| Cold Wave | Relatively High | 90.3 | $10M |
| Winter Weather | Relatively High | 87.9 | $492K |
| Heat Wave | Relatively Moderate | 87.5 | $3.5M |
| Drought | Relatively Moderate | 81.8 | $1.5M |
| Riverine Flooding | Relatively Moderate | 79.8 | $27M |
| Ice Storm | Relatively Moderate | 75.7 | $428K |
| Lightning | Relatively Moderate | 74.5 | $830K |
| Landslide | Relatively Low | 79.1 | $20K |
| Wildfire | Relatively Low | 64.4 | $164K |
| Earthquake | Very Low | 45.1 | $294K |
| Hurricane | Very Low | 13.6 | $5K |
Source: FEMA National Risk Index, December 2025 release. A model of future loss, not a count of past events. FEMA's National Risk Index map.
What the record holds
| Hazard | Records | Deaths | Damage | Rank in state | Rank in U.S. |
|---|---|---|---|---|---|
| Severe thunderstorm wind | 282 | 1 | $83M | 20th of 99 | 1220th of 3,080 |
| Hail | 229 | 0 | $77M | 25th of 99 | 718th of 3,080 |
| Winter storms | 165 | 0 | $1.5M | 21st of 99 | 444th of 3,077 |
| Floods | 75 | 0 | $321M | 43rd of 99 | 796th of 3,080 |
| Tornadoes | 46 | 1 | $73M | 49th of 99 | 706th of 3,080 |
| Extreme cold | 22 | 2 | $374K | 90th of 99 | 751st of 3,076 |
| High wind and dust storms | 16 | 0 | $1.6M | 82nd of 99 | 1602nd of 3,080 |
| Drought | 15 | 0 | $48M | 85th of 99 | 1499th of 3,063 |
| Lightning | 10 | 0 | $1.5M | 9th of 99 | 450th of 3,080 |
| Heavy rain | 7 | 0 | $3K | 69th of 99 | 792nd of 3,080 |
| Heat | 5 | 0 | – | 50th of 99 | 1607th of 3,076 |
Source: NOAA NCEI Storm Events Database, 1950 to 2026-06-30; damage in 2025 dollars. Search the record at NCEI.
The full Johnson County record: every hazard by year and month, the deadliest events and FEMA's declarations.