Mason County, Illinois Natural Disaster Risk
FEMA National Risk Index assessment · IL
LowComposite Risk Score
National percentile: 43th
Mason County faces low composite natural disaster risk (NRI Risk Index score 43.0, 43th national percentile), driven primarily by drought and strong wind 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 Mason County at low composite risk, with a National Risk Index score of 43.0 out of 100 — placing it in the 43rd 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 drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $1M in expected annual loss and about 4.42 events per year; strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at Medium risk — $985K in expected annual loss and about 5.15 events per year; and cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $2M in expected annual loss and about 4.37 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 13K.
Beyond physical exposure, Mason County has a medium 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: Mason County has received 18 federal disaster declarations since 1968, including 6 for flood events and 4 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 102 Illinois counties, Mason County ranks #65 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 4.42 / yr | $1M |
| Strong Wind | Medium | 5.15 / yr | $985K |
| Cold Wave | Medium | 4.37 / yr | $2M |
| Earthquake | Low | 0.00 / yr | $510K |
| Hail | Low | 3.64 / yr | $392K |
| Heat Wave | Low | 7.11 / yr | $473K |
| Tornado | Low | 0.59 / yr | $1M |
| Riverine Flood | Low | 0.93 / yr | $6M |
| Ice Storm | Low | 1.81 / yr | $63K |
| Landslide | Very Low | 0.10 / yr | $480 |
| Winter Weather | Low | 9.74 / yr | $26K |
| Hurricane | Very Low | 0.01 / yr | $7K |
| Lightning | Very Low | 47.41 / yr | $52K |
| Wildfire | Very Low | 0.00 / yr | $584 |
| 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
Mason County has received 18 federal disaster declarations since 1968, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (6), Severe Storm (4), Snowstorm (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 |
| December 2006 | Snowstorm | Snow |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2003 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| May 2002 | Tornado | Severe Storms, Tornadoes and Flooding |
| January 1999 | Snowstorm | Il-Winter Storm 1/1/99 |
| May 1995 | Severe Storm | Severe Storms and Flooding |
Showing the 10 most recent of 18 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Mason County?
Mason County has a composite FEMA National Risk Index score of 43.0 out of 100, placing it in the Low category and the 43th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Mason County?
The three highest-rated hazards are Drought (Medium, $1M EAL), Strong Wind (Medium, $985K EAL), Cold Wave (Medium, $2M EAL). These account for most of the county's expected annual losses.
How does Mason County compare to other Illinois counties?
Mason County ranks #65 of 102 Illinois counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Mason County had?
FEMA records 18 federal disaster declarations for Mason County since 1968, most often 6 for flood events and 4 for severe storm 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. Mason County's $12M EAL is a statistical average, not a guarantee for any specific year or address.