Cass County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
Very LowComposite Risk Score
National percentile: 39th
Cass County faces very low composite natural disaster risk (NRI Risk Index score 38.6, 39th national percentile), driven primarily by cold wave and drought exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Cass County at very low composite risk, with a National Risk Index score of 38.6 out of 100 — placing it in the 39th national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Cass County's expected losses come from cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $5M in expected annual loss and about 3.58 events per year; drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $1M in expected annual loss and about 4.40 events per year; and heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Low risk — $731K in expected annual loss and about 8.21 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 13K.
Beyond physical exposure, Cass 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 county's disaster history tells the same story: Cass County has received 21 federal disaster declarations since 1973, including 7 for flood events and 7 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes (tornado), declared in December 2021.
Among 102 Illinois counties, Cass County ranks #71 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 3.58 / yr | $5M |
| Drought | Medium | 4.40 / yr | $1M |
| Heat Wave | Low | 8.21 / yr | $731K |
| Strong Wind | Medium | 5.01 / yr | $780K |
| Landslide | Very Low | 0.14 / yr | $2K |
| Earthquake | Very Low | 0.00 / yr | $248K |
| Hail | Low | 3.71 / yr | $172K |
| Tornado | Low | 0.35 / yr | $602K |
| Riverine Flood | Very Low | 1.07 / yr | $3M |
| Ice Storm | Very Low | 1.55 / yr | $24K |
| Winter Weather | Very Low | 9.26 / yr | $20K |
| Lightning | Very Low | 46.22 / yr | $57K |
| Hurricane | Very Low | 0.01 / yr | $4K |
| Wildfire | Very Low | 0.00 / yr | $107 |
| 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
Cass County has received 21 federal disaster declarations since 1973, most recently Severe Storms, Straight-Line Winds, and Tornadoes in December 2021. Most frequent causes: Flood (7), Severe Storm (7), Tornado (2).
| Declared | Type | Disaster |
|---|---|---|
| December 2021 | Tornado | Severe Storms, Straight-Line Winds, and Tornadoes |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2019 | Flood | Severe Storms and Flooding |
| 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 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2002 | Tornado | Severe Storms, Tornadoes and Flooding |
| January 1999 | Snowstorm | Il-Winter Storm 1/1/99 |
Showing the 10 most recent of 21 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Cass County?
Cass County has a composite FEMA National Risk Index score of 38.6 out of 100, placing it in the Very Low category and the 39th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Cass County?
The three highest-rated hazards are Cold Wave (Medium, $5M EAL), Drought (Medium, $1M EAL), Heat Wave (Low, $731K EAL). These account for most of the county's expected annual losses.
How does Cass County compare to other Illinois counties?
Cass County ranks #71 of 102 Illinois counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Cass County had?
FEMA records 21 federal disaster declarations for Cass County since 1973, most often 7 for flood events and 7 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes, declared in December 2021.
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. Cass County's $12M EAL is a statistical average, not a guarantee for any specific year or address.