riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Grundy County Disaster Risk

Grundy County, Illinois

FEMA Risk Rating

Relatively Low

National Percentile

67th

of 3,144 counties

State Rank

#37

of 102 (1 = highest risk)

Flood Risk

66th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 66% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 16% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 69% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 56% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 9% of US counties

Risk Overview

About Natural Disaster Risk in Grundy County, Illinois

Grundy County moderately above U.S. risk

Grundy County's composite risk score of 66.51 exceeds the national average, though its "Relatively Low" rating indicates manageable hazard exposure. The county faces somewhat elevated natural disaster risk compared to typical American regions, primarily due to flood and tornado hazards.

Above Illinois state average

Grundy's 66.51 score exceeds Illinois's state average of 54.46 by 12 points, placing it in the upper range of Illinois's risk profile. This gap reflects Grundy's notably higher exposure to flooding and tornado events.

More hazardous than most central Illinois

Grundy's 66.51 substantially exceeds Fayette (48.76) and Effingham (53.75) but remains well below Franklin County's elevated 80.95. Grundy residents face more natural disaster exposure than most of northern-central Illinois.

Flooding and tornadoes are primary concerns

Grundy County's flood risk (66.48) and tornado risk (68.77) are nearly equally serious threats, both ranking well above state norms. Wildfire (15.68) and earthquake (56.33) pose secondary considerations, while hurricane risk (9.39) is minimal.

Prioritize flood and wind coverage

Grundy County residents must secure flood insurance through the National Flood Insurance Program, as standard homeowners policies exclude flood damage and Grundy's 66.48 score reflects real exposure. Verify comprehensive tornado/wind coverage in your homeowners policy, which is critical given the 68.77 tornado risk score.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Grundy County

Top Hazards by Exposure

  1. #1
    TornadoPrepare
    69th percentile
  2. #2
    FloodPrepare
    66th percentile
  3. #3
    EarthquakePrepare
    56th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Grundy County

Risk Verdict

Grundy County's FEMA risk score places it at the 67th percentile nationally, indicating lower-than-typical exposure for a U.S. county. A moderate composite score often means one or two hazard categories are doing the heavy lifting — knowing which ones matters for preparation.

Hazard Breakdown

Tornado risk is Grundy County's dominant natural hazard, ranked at the 69th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 66th percentile nationally. Additional tracked hazards include earthquake (56th percentile), wildfire (16th percentile), hurricane (9th percentile).

Preparedness Context

Tornado exposure at the 69th percentile nationally makes Grundy County a county where a battery-powered weather radio — not just smartphone apps — is a worthwhile household investment, given that mobile networks often fail during severe storms. Flood is the second hazard driver for Grundy County at the 66th percentile nationally, meaning households should maintain awareness of both severe-weather and flood-specific warning systems. In Grundy County, tornado watches indicate favorable atmospheric conditions while warnings mean rotation has been detected — households benefit from understanding this distinction so they shelter immediately on a warning, not after seeking visual confirmation.

Regional Context

The Illinois county average is 12.0 composite points below Grundy County's score, a gap that reflects the county's elevated position in the state's hazard distribution.

Is your household prepared for Grundy County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Grundy County, IL?
Grundy County has a FEMA National Risk Index rating of Relatively Low, placing it in the 67th 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 Grundy County?
Grundy County is evaluated for five major natural hazard types: tornado (69th percentile), flooding (66th percentile), earthquake (56th percentile), wildfire (16th percentile), hurricane (9th percentile). The highest-risk hazard is tornado at the 69th 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 Grundy County risk compare to the Illinois average?
Grundy County's composite risk percentile is 67th, compared to the Illinois state average of 55th percentile. The state's overall risk rating is Relatively Low. This means Grundy County faces higher natural disaster risk than the typical county in Illinois.
Is Grundy County at risk for tornado?
Yes, Grundy County's tornado risk is at the 69th percentile nationally. This is above the national median. For flooding specifically, Grundy County is at the 66th 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 Grundy County higher risk than average?
Grundy County's composite risk score of 67th percentile is above the Illinois state average of 55th percentile. This elevated risk is driven by tornado exposure (69th 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.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, 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.