Johnson County, IL
FEMA National Risk Index scores, disaster declarations & hazard data
Johnson County has experienced 7 federally declared disasters since 1973, most recently Covid-19 in 2020. Its overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Johnson County's highest-rated hazards are earthquake, heat wave, and strong wind, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Recorded storm events have increased 33% over the past five years compared to the prior five-year period.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Johnson County has been designated in 7 declarations since 1973, covering 6 disaster types including biological (2), hurricane (1), snowstorm (1).
| Year | Type | Event name |
|---|---|---|
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2009 | Severe Storm | Severe Winter Storm |
| 2005 | Snowstorm | Record/Near Record Snow |
| 2005 | Hurricane | Hurricane Katrina Evacuation |
| 2002 | Tornado | Severe Storms, Tornadoes And Flooding |
| 1973 | Flood | Severe Storms & Flooding |
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Very Low | 11.3 | 0 | 0 | — |
| Inland Flooding | Relatively Low | 37.9 | 5 | 1 | $15K |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Relatively Moderate | 91 | 1 | — | — |
| Heat Wave | Relatively Low | 68.9 | 45 | 0 | — |
| Tornado | Relatively Low | 56 | 3 | 0 | $1.8M |
| Hurricane | Very Low | 38.1 | 0 | 0 | — |
| Hail | Relatively Low | 66.5 | 10 | 0 | — |
| Strong Wind | Relatively Moderate | 68.8 | 0 | 0 | — |
| Winter Weather | Relatively Moderate | 64.6 | 0 | 0 | — |
| Ice Storm | Relatively Moderate | 68.4 | — | — | — |
| Cold Wave | Relatively Low | 64 | — | — | — |
| Lightning | Relatively Low | 33.8 | 0 | 0 | — |
| Drought | Relatively Low | 52.5 | 0 | 0 | — |
| Landslide | Very Low | 44 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Johnson County ranks in the 38th percentile (Low) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 38th | Low |
| Socioeconomic status | 30th | Low |
| Household characteristics | 37th | Low |
| Racial & ethnic minority status | 50th | Moderate |
| Housing type & transportation | 53rd | Moderate |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 36th | Relatively Low |
| Risk to homes | 33rd | Relatively Low |
| Buildings in direct exposure zone | 77.8% | — |
NOAA tracked 63 weather events in this county over 2016–2025: 27 in 2016–20 vs 36 in 2021–25 (+33% — frequency increasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Johnson County?
According to the FEMA National Risk Index, the highest-risk hazards in Johnson County, Illinois are earthquake, heat wave, and strong wind. The county's overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Has Johnson County received federal disaster declarations?
Yes. Johnson County has received 7 federal disaster declarations since 1973, including declarations in 2020. The most common disaster type on record is biological (2 declarations).
Has Johnson County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Johnson County since the start of 2024. Its most recent declaration on record is Covid-19 in 2020.
How does Johnson County's natural hazard risk compare to nearby counties?
Among neighboring counties, Williamson County, IL has the highest overall natural hazard risk (Relatively Moderate) and Pope County, IL has the lowest (Very Low). Johnson County is rated Relatively Low overall.
How is Johnson County's composite disaster risk index calculated?
Johnson County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Johnson County's composite score of 51 means its overall natural hazard risk is higher than 51% of US counties.