DeKalb County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
LowComposite Risk Score
National percentile: 81th
DeKalb County faces low composite natural disaster risk (NRI Risk Index score 80.8, 81th national percentile), driven primarily by cold wave and tornado exposure. Expected annual loss across all 18 hazard types is $47M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
DeKalb County carries a low composite natural disaster risk, with a National Risk Index score of 80.8 out of 100 — placing it in the 81st 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.
Most of DeKalb County's expected losses come from cold wave (prolonged spells of dangerously low temperatures) at High risk — $12M in expected annual loss and about 5.89 events per year; tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $7M in expected annual loss and about 0.53 events per year; and riverine flood (rivers and streams overflowing their banks after heavy rain or snowmelt) at Medium risk — $24M in expected annual loss and about 1.14 events per year. Across all hazards, FEMA estimates $47M in expected annual loss for a population of 100K.
Beyond physical exposure, DeKalb County has a low social vulnerability rating (how susceptible the population is to harm) and a 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 federal record bears this out: DeKalb County has received 12 federal disaster declarations since 1973, including 3 for flood events and 3 for snowstorm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 102 Illinois counties, DeKalb County ranks #22 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 5.89 / yr | $12M |
| Tornado | Medium | 0.53 / yr | $7M |
| Riverine Flood | Medium | 1.14 / yr | $24M |
| Strong Wind | Medium | 6.54 / yr | $1M |
| Earthquake | Low | 0.00 / yr | $1M |
| Drought | Medium | 8.31 / yr | $752K |
| Ice Storm | Medium | 0.62 / yr | $147K |
| Heat Wave | Low | 3.42 / yr | $600K |
| Lightning | Low | 42.03 / yr | $253K |
| Hail | Low | 4.57 / yr | $158K |
| Winter Weather | Low | 15.00 / yr | $36K |
| Landslide | Very Low | 0.09 / yr | $304 |
| Hurricane | Very Low | 0.01 / yr | $6K |
| Wildfire | Very Low | 0.00 / yr | $2K |
| 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
DeKalb County has received 12 federal disaster declarations since 1973, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (3), Snowstorm (3), Severe Storm (3).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| 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 |
| December 2006 | Snowstorm | Snow |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| July 1996 | Severe Storm | Severe Storms and Flooding |
| January 1979 | Snowstorm | Blizzards & Snowstorms |
Showing the 10 most recent of 12 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for DeKalb County?
DeKalb County has a composite FEMA National Risk Index score of 80.8 out of 100, placing it in the Low category and the 81th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in DeKalb County?
The three highest-rated hazards are Cold Wave (High, $12M EAL), Tornado (Medium, $7M EAL), Riverine Flood (Medium, $24M EAL). These account for most of the county's expected annual losses.
How does DeKalb County compare to other Illinois counties?
DeKalb County ranks #22 of 102 Illinois counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has DeKalb County had?
FEMA records 12 federal disaster declarations for DeKalb County since 1973, most often 3 for flood events and 3 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. DeKalb County's $47M EAL is a statistical average, not a guarantee for any specific year or address.