Winnebago County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
MediumComposite Risk Score
National percentile: 92th
Winnebago County faces medium composite natural disaster risk (NRI Risk Index score 92.4, 92th national percentile), driven primarily by cold wave and strong wind exposure. Expected annual loss across all 18 hazard types is $122M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Winnebago County is medium, with a National Risk Index score of 92.4 out of 100 — placing it in the 92nd national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Winnebago County's expected losses come from cold wave (prolonged spells of dangerously low temperatures) at High risk — $20M in expected annual loss and about 5.74 events per year; strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at High risk — $4M in expected annual loss and about 6.05 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at High risk — $19M in expected annual loss and about 0.44 events per year. Across all hazards, FEMA estimates $122M in expected annual loss for a population of 285K.
Beyond physical exposure, Winnebago 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: Winnebago County has received 19 federal disaster declarations since 1967, including 6 for snowstorm events and 5 for flood events. The most recent was Severe Storms, Tornadoes, Straight-Line Winds, and Floodng (flood), declared in September 2024.
Among 102 Illinois counties, Winnebago County ranks #8 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 5.74 / yr | $20M |
| Strong Wind | High | 6.05 / yr | $4M |
| Tornado | High | 0.44 / yr | $19M |
| Hail | High | 4.52 / yr | $4M |
| Riverine Flood | High | 2.07 / yr | $68M |
| Lightning | High | 40.01 / yr | $1M |
| Heat Wave | Medium | 3.26 / yr | $2M |
| Ice Storm | High | 0.72 / yr | $615K |
| Winter Weather | Medium | 14.74 / yr | $275K |
| Earthquake | Low | 0.00 / yr | $2M |
| Drought | Low | 9.94 / yr | $246K |
| Landslide | Very Low | 0.09 / yr | $1K |
| Wildfire | Very Low | 0.00 / yr | $17K |
| Hurricane | Very Low | 0.01 / yr | $6K |
| 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
Winnebago County has received 19 federal disaster declarations since 1967, most recently Severe Storms, Tornadoes, Straight-Line Winds, and Floodng in September 2024. Most frequent causes: Snowstorm (6), Flood (5), Severe Storm (4).
| Declared | Type | Disaster |
|---|---|---|
| September 2024 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Floodng |
| 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 |
| August 2010 | Severe Storm | Severe Storms and Flooding |
| June 2008 | Severe Storm | Severe Storms and Flooding |
| March 2008 | Snowstorm | Record Snow and Near Record Snow |
| August 2007 | Severe Storm | Severe Storms and Flooding |
| December 2006 | Snowstorm | Snow |
Showing the 10 most recent of 19 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Winnebago County?
Winnebago County has a composite FEMA National Risk Index score of 92.4 out of 100, placing it in the Medium category and the 92th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Winnebago County?
The three highest-rated hazards are Cold Wave (High, $20M EAL), Strong Wind (High, $4M EAL), Tornado (High, $19M EAL). These account for most of the county's expected annual losses.
How does Winnebago County compare to other Illinois counties?
Winnebago County ranks #8 of 102 Illinois counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Winnebago County had?
FEMA records 19 federal disaster declarations for Winnebago County since 1967, most often 6 for snowstorm events and 5 for flood events. The most recent was Severe Storms, Tornadoes, Straight-Line Winds, and Floodng, declared in September 2024.
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. Winnebago County's $122M EAL is a statistical average, not a guarantee for any specific year or address.