Jefferson County
Wisconsin — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 76th
Jefferson County faces low composite natural disaster risk (NRI Risk Index score 75.8, 76th national percentile), driven primarily by hail and tornado exposure. Expected annual loss across all 18 hazard types is $42M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Hail | Medium | 3.96 / yr | $3M |
| Tornado | Medium | 0.43 / yr | $7M |
| Cold Wave | Medium | 5.47 / yr | $6M |
| Lightning | Medium | 36.91 / yr | $896K |
| Riverine Flood | Medium | 1.57 / yr | $23M |
| Heat Wave | Low | 3.42 / yr | $1M |
| Strong Wind | Medium | 4.55 / yr | $1M |
| Winter Weather | Low | 15.11 / yr | $104K |
| Landslide | Very Low | 0.11 / yr | $3K |
| Ice Storm | Low | 0.60 / yr | $76K |
| Earthquake | Very Low | 0.00 / yr | $225K |
| Wildfire | Very Low | 0.00 / yr | $31K |
| Drought | Low | 1.64 / yr | $64K |
| Hurricane | Very Low | 0.01 / yr | $4K |
| 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 |
Frequently Asked Questions
What is the overall natural disaster risk for Jefferson County?
Jefferson County has a composite FEMA National Risk Index score of 75.8 out of 100, placing it in the Low category and the 76th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Jefferson County?
The three highest-rated hazards are Hail (Medium, $3M EAL), Tornado (Medium, $7M EAL), Cold Wave (Medium, $6M EAL). These account for most of the county's expected annual losses.
How does Jefferson County compare to other Wisconsin counties?
Jefferson County ranks #18 of 72 Wisconsin counties for overall natural disaster risk, with a low rating.
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. Jefferson County's $42M EAL is a statistical average, not a guarantee for any specific year or address.