Williamson County
Texas — Natural Disaster Risk Assessment
MediumComposite Risk Score
National percentile: 90th
Williamson County faces medium composite natural disaster risk (NRI Risk Index score 90.1, 90th national percentile), driven primarily by hail and winter weather exposure. Expected annual loss across all 18 hazard types is $137M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Hail | High | 3.95 / yr | $14M |
| Winter Weather | Very High | 3.74 / yr | $1M |
| Cold Wave | High | 0.63 / yr | $21M |
| Tornado | High | 0.62 / yr | $17M |
| Riverine Flood | Medium | 3.64 / yr | $71M |
| Heat Wave | Medium | 10.00 / yr | $5M |
| Lightning | High | 49.36 / yr | $2M |
| Wildfire | Low | 0.00 / yr | $2M |
| Ice Storm | Medium | 0.65 / yr | $403K |
| Drought | Medium | 59.30 / yr | $964K |
| Hurricane | Low | 0.04 / yr | $860K |
| Strong Wind | Medium | 1.72 / yr | $1M |
| Earthquake | Very Low | 0.00 / yr | $197K |
| Landslide | Very Low | 0.13 / yr | $278 |
| 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 Williamson County?
Williamson County has a composite FEMA National Risk Index score of 90.1 out of 100, placing it in the Medium category and the 90th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Williamson County?
The three highest-rated hazards are Hail (High, $14M EAL), Winter Weather (Very High, $1M EAL), Cold Wave (High, $21M EAL). These account for most of the county's expected annual losses.
How does Williamson County compare to other Texas counties?
Williamson County ranks #24 of 254 Texas 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. Williamson County's $137M EAL is a statistical average, not a guarantee for any specific year or address.