McHenry County, IL
FEMA National Risk Index scores, disaster declarations & hazard data
McHenry County has experienced 16 federally declared disasters since 1965, most recently Covid-19 in 2020. Its overall natural hazard risk is rated Relatively Moderate — near the middle compared to other US counties.
McHenry County's highest-rated hazards are cold wave, tornado, and inland flooding, with its top risk rated "Relatively High" by FEMA's National Risk Index. Recorded storm events have increased 20% over the past five years compared to the prior five-year period. Community vulnerability is relatively low (9th percentile nationally), indicating stronger recovery capacity than most US counties.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. McHenry County has been designated in 16 declarations since 1965, covering 5 disaster types including snowstorm (6), flood (5), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2013 | Flood | Severe Storms, Straight-Line Winds, And Flooding |
| 2011 | Snowstorm | Severe Winter Storm And Snowstorm |
| 2008 | Snowstorm | Record Snow And Near Record Snow |
| 2007 | Snowstorm | Snow |
| 2005 | Hurricane | Hurricane Katrina Evacuation |
| 2001 | Snowstorm | Illinois Winter Snow Storms |
| 1999 | Snowstorm | Il-Winter Storm 1/1/99 |
| 1993 | Flood | Severe Storms & Flooding |
Showing the 10 most recent of 16 total declarations since 1965.
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 | 31.6 | 0 | 0 | — |
| Inland Flooding | Relatively Moderate | 93.1 | 18 | 0 | $3.9M |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Relatively Low | 74.7 | — | — | — |
| Heat Wave | Relatively Low | 75.5 | 5 | 0 | — |
| Tornado | Relatively High | 96.3 | 7 | 0 | — |
| Hurricane | Very Low | 10.3 | 0 | 0 | — |
| Hail | Relatively Moderate | 79.5 | 32 | 0 | — |
| Strong Wind | Relatively High | 85.5 | 0 | 0 | — |
| Winter Weather | Relatively Moderate | 79.2 | 0 | 0 | — |
| Ice Storm | Relatively Low | 55.6 | — | — | — |
| Cold Wave | Relatively High | 96.7 | — | — | — |
| Lightning | Relatively Moderate | 73.5 | 4 | 0 | $105K |
| Drought | Relatively Low | 59.2 | 0 | 0 | — |
| Landslide | Very Low | 57.2 | 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
McHenry County ranks in the 9th percentile (Very 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 | 9th | Very low |
| Socioeconomic status | 14th | Very low |
| Household characteristics | 24th | Very low |
| Racial & ethnic minority status | 55th | Moderate |
| Housing type & transportation | 4th | Very low |
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 | 14th | Very Low |
| Risk to homes | 14th | Very Low |
| Buildings in direct exposure zone | 26.8% | — |
NOAA tracked 66 weather events in this county over 2016–2025: 30 in 2016–20 vs 36 in 2021–25 (+20% — 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 McHenry County?
According to the FEMA National Risk Index, the highest-risk hazards in McHenry County, Illinois are cold wave, tornado, and inland flooding. The county's overall natural hazard risk is rated Relatively Moderate — near the middle compared to other US counties.
Has McHenry County received federal disaster declarations?
Yes. McHenry County has received 16 federal disaster declarations since 1965, including declarations in 2020. The most common disaster type on record is snowstorm (6 declarations).
Has McHenry County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for McHenry County since the start of 2024. Its most recent declaration on record is Covid-19 in 2020.
How does McHenry County's natural hazard risk compare to nearby counties?
Among neighboring counties, Lake County, IL has the highest overall natural hazard risk (Relatively High) and Boone County, IL has the lowest (Relatively Low). McHenry County is rated Relatively Moderate overall.
How is McHenry County's composite disaster risk index calculated?
McHenry 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. McHenry County's composite score of 91 means its overall natural hazard risk is higher than 91% of US counties.