riskbycounty
FEMA National Risk Index

McHenry County Disaster Risk

McHenry County, Illinois

FEMA Risk Rating

Relatively Moderate

National Percentile

91th

of 3,144 counties

State Rank

#10

of 102 (1 = highest risk)

Flood Risk

93th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Moderate

Higher than 93% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 32% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively High

Higher than 96% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 75% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 10% of US counties

Risk Advisory: McHenry County

Risk Verdict

McHenry County has a relatively moderate overall disaster risk profile, scoring in the 91th percentile nationally. While not in the highest tier, this county faces meaningful hazard exposure. Residents are encouraged to understand their specific risks and maintain emergency supplies.

Hazard Breakdown

Tornado risk is the dominant hazard for McHenry County, scoring in the 96th percentile nationally. It is followed by flood risk at the 93th percentile. Additional hazards include earthquake (75th), wildfire (32th), hurricane (10th).

Preparedness Context

With tornado risk as the top concern, McHenry County residents should identify a safe room or interior space on the lowest floor, have a NOAA weather radio, and practice tornado drills with your household. Secondary risks such as flood also warrant attention in household and community preparedness planning. FEMA recommends all households maintain at least 72 hours of food, water, and medication supplies regardless of specific hazard exposure.

Regional Context

McHenry County is significantly riskier than the average county in Illinois. Its composite risk score is 36.3 points higher than the state average, meaning residents face above-average exposure to natural hazards compared to their neighbors.

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Frequently Asked Questions

What is the natural disaster risk in McHenry County, IL?
McHenry County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 91th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect McHenry County?
McHenry County is evaluated for five major natural hazard types: tornado (96th percentile), flooding (93th percentile), earthquake (75th percentile), wildfire (32th percentile), hurricane (10th percentile). The highest-risk hazard is tornado at the 96th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does McHenry County risk compare to the Illinois average?
McHenry County's composite risk percentile is 91th, compared to the Illinois state average of 55th percentile. The state's overall risk rating is Relatively Low. This means McHenry County faces higher natural disaster risk than the typical county in Illinois.
Is McHenry County at risk for tornado?
Yes, McHenry County's tornado risk is at the 96th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, McHenry County is at the 93th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is McHenry County higher risk than average?
McHenry County's composite risk score of 91th percentile is above the Illinois state average of 55th percentile. This elevated risk is driven by tornado exposure (96th percentile), along with flooding and earthquake risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Peoria County

Illinois

-0.1

Relatively Moderate

91th percentile

Champaign County

Illinois

-0.3

Relatively Moderate

90th percentile

Sangamon County

Illinois

+0.9

Relatively Moderate

92th percentile

By Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.

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