Grundy County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
LowComposite Risk Score
National percentile: 67th
Grundy County faces low composite natural disaster risk (NRI Risk Index score 66.5, 67th national percentile), driven primarily by cold wave and tornado exposure. Expected annual loss across all 18 hazard types is $50M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Grundy County is low, with a National Risk Index score of 66.5 out of 100 — placing it in the 67th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in cold wave (prolonged spells of dangerously low temperatures) at High risk — $20M in expected annual loss and about 4.89 events per year; tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $5M in expected annual loss and about 0.39 events per year; and riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at Low risk — $22M in expected annual loss and about 1.25 events per year. Across all hazards, FEMA estimates $50M in expected annual loss for a population of 52K.
Beyond physical exposure, Grundy County has a very low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The county's disaster history tells the same story: Grundy County has received 15 federal disaster declarations since 1972, including 4 for flood events and 4 for snowstorm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 102 Illinois counties, Grundy County ranks #37 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 4.89 / yr | $20M |
| Tornado | Medium | 0.39 / yr | $5M |
| Riverine Flood | Low | 1.25 / yr | $22M |
| Strong Wind | Medium | 5.97 / yr | $2M |
| Earthquake | Very Low | 0.00 / yr | $755K |
| Heat Wave | Low | 4.32 / yr | $592K |
| Drought | Low | 2.18 / yr | $101K |
| Landslide | Very Low | 0.08 / yr | $817 |
| Winter Weather | Low | 14.11 / yr | $47K |
| Ice Storm | Very Low | 0.82 / yr | $46K |
| Lightning | Very Low | 44.17 / yr | $122K |
| Wildfire | Very Low | 0.00 / yr | $11K |
| Hail | Very Low | 4.09 / yr | $76K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Grundy County has received 15 federal disaster declarations since 1972, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (4), Snowstorm (4), Severe Storm (3).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| November 2013 | Tornado | Severe Storms, Straight-Line Winds, and Tornadoes |
| May 2013 | Flood | Severe Storms, Straight-Line Winds, and Flooding |
| March 2011 | Snowstorm | Severe Winter Storm and Snowstorm |
| October 2008 | Severe Storm | Severe Storms and Flooding |
| September 2007 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| January 2001 | Snowstorm | Illinois Winter Snow Storms |
| January 1999 | Snowstorm | Il-Winter Storm 1/1/99 |
Showing the 10 most recent of 15 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Grundy County?
Grundy County has a composite FEMA National Risk Index score of 66.5 out of 100, placing it in the Low category and the 67th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Grundy County?
The three highest-rated hazards are Cold Wave (High, $20M EAL), Tornado (Medium, $5M EAL), Riverine Flood (Low, $22M EAL). These account for most of the county's expected annual losses.
How does Grundy County compare to other Illinois counties?
Grundy County ranks #37 of 102 Illinois counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Grundy County had?
FEMA records 15 federal disaster declarations for Grundy County since 1972, most often 4 for flood events and 4 for snowstorm events. The most recent was Covid-19 Pandemic, declared in March 2020.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Grundy County's $50M EAL is a statistical average, not a guarantee for any specific year or address.