Waukesha County
Wisconsin — Natural Disaster Risk Assessment
MediumComposite Risk Score
National percentile: 89th
Waukesha County faces medium composite natural disaster risk (NRI Risk Index score 88.9, 89th national percentile), driven primarily by cold wave and hail exposure. Expected annual loss across all 18 hazard types is $138M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 5.32 / yr | $30M |
| Hail | High | 3.68 / yr | $6M |
| Tornado | High | 0.37 / yr | $24M |
| Heat Wave | Medium | 3.21 / yr | $6M |
| Riverine Flood | Medium | 1.75 / yr | $68M |
| Winter Weather | High | 15.05 / yr | $553K |
| Ice Storm | Medium | 0.63 / yr | $841K |
| Landslide | Low | 0.12 / yr | $6K |
| Lightning | Medium | 36.33 / yr | $606K |
| Earthquake | Very Low | 0.00 / yr | $724K |
| Strong Wind | Medium | 4.13 / yr | $1M |
| Wildfire | Very Low | 0.00 / yr | $83K |
| Drought | Low | 1.23 / yr | $55K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| 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 Waukesha County?
Waukesha County has a composite FEMA National Risk Index score of 88.9 out of 100, placing it in the Medium category and the 89th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Waukesha County?
The three highest-rated hazards are Cold Wave (High, $30M EAL), Hail (High, $6M EAL), Tornado (High, $24M EAL). These account for most of the county's expected annual losses.
How does Waukesha County compare to other Wisconsin counties?
Waukesha County ranks #4 of 72 Wisconsin counties for overall natural disaster risk, with a medium 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. Waukesha County's $138M EAL is a statistical average, not a guarantee for any specific year or address.