Mercer County
Pennsylvania — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 78th
Mercer County faces low composite natural disaster risk (NRI Risk Index score 77.7, 78th national percentile), driven primarily by riverine flood and lightning exposure. Expected annual loss across all 18 hazard types is $34M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Riverine Flood | Medium | 2.50 / yr | $29M |
| Lightning | High | 39.56 / yr | $926K |
| Winter Weather | Medium | 16.84 / yr | $168K |
| Hail | Medium | 3.79 / yr | $647K |
| Strong Wind | Medium | 2.28 / yr | $981K |
| Hurricane | Low | 0.02 / yr | $306K |
| Tornado | Low | 0.28 / yr | $1M |
| Earthquake | Very Low | 0.00 / yr | $269K |
| Landslide | Very Low | 0.20 / yr | $737 |
| Ice Storm | Low | 0.45 / yr | $53K |
| Wildfire | Very Low | 0.00 / yr | $19K |
| Heat Wave | Very Low | 1.05 / yr | $110K |
| Cold Wave | Very Low | 3.63 / yr | $255K |
| 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 77.7 out of 100, placing it in the Low category and the 78th 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 Riverine Flood (Medium, $29M EAL), Lightning (High, $926K EAL), Winter Weather (Medium, $168K EAL). These account for most of the county's expected annual losses.
How does Mercer County compare to other Pennsylvania counties?
Mercer County ranks #27 of 67 Pennsylvania 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. Mercer County's $34M EAL is a statistical average, not a guarantee for any specific year or address.