Mercer County
Ohio — Natural Disaster Risk Assessment
Very LowComposite Risk Score
National percentile: 32th
Mercer County faces very low composite natural disaster risk (NRI Risk Index score 31.6, 32th national percentile), driven primarily by earthquake and tornado exposure. Expected annual loss across all 18 hazard types is $18M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Earthquake | Low | 0.00 / yr | $2M |
| Tornado | Medium | 0.31 / yr | $4M |
| Hail | Low | 3.46 / yr | $769K |
| Strong Wind | Low | 3.51 / yr | $941K |
| Ice Storm | Low | 0.79 / yr | $119K |
| Riverine Flood | Low | 2.25 / yr | $9M |
| Hurricane | Very Low | 0.01 / yr | $49K |
| Cold Wave | Low | 4.84 / yr | $759K |
| Winter Weather | Low | 11.74 / yr | $48K |
| Lightning | Low | 42.85 / yr | $162K |
| Landslide | Very Low | 0.08 / yr | $225 |
| Heat Wave | Very Low | 4.00 / yr | $83K |
| Wildfire | Very Low | 0.00 / yr | $4K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Drought | 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 Mercer County?
Mercer County has a composite FEMA National Risk Index score of 31.6 out of 100, placing it in the Very Low category and the 32th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Mercer County?
The three highest-rated hazards are Earthquake (Low, $2M EAL), Tornado (Medium, $4M EAL), Hail (Low, $769K EAL). These account for most of the county's expected annual losses.
How does Mercer County compare to other Ohio counties?
Mercer County ranks #73 of 88 Ohio counties for overall natural disaster risk, with a very 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. Mercer County's $18M EAL is a statistical average, not a guarantee for any specific year or address.