Allegheny County
Pennsylvania — Natural Disaster Risk Assessment
HighComposite Risk Score
National percentile: 98th
Allegheny County faces high composite natural disaster risk (NRI Risk Index score 98.1, 98th national percentile), driven primarily by riverine flood and cold wave exposure. Expected annual loss across all 18 hazard types is $354M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Riverine Flood | Very High | 7.32 / yr | $295M |
| Cold Wave | Very High | 2.84 / yr | $32M |
| Strong Wind | High | 2.35 / yr | $4M |
| Ice Storm | Very High | 0.40 / yr | $2M |
| Heat Wave | Medium | 1.95 / yr | $5M |
| Lightning | High | 42.59 / yr | $2M |
| Winter Weather | High | 11.21 / yr | $586K |
| Tornado | High | 0.28 / yr | $8M |
| Earthquake | Low | 0.00 / yr | $4M |
| Landslide | Low | 1.50 / yr | $42K |
| Hurricane | Low | 0.03 / yr | $1M |
| Wildfire | Very Low | 0.00 / yr | $91K |
| Hail | Very Low | 3.21 / yr | $135K |
| Avalanche | Very Low | 0.01 / yr | $94 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.01 / 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 Allegheny County?
Allegheny County has a composite FEMA National Risk Index score of 98.1 out of 100, placing it in the High category and the 98th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Allegheny County?
The three highest-rated hazards are Riverine Flood (Very High, $295M EAL), Cold Wave (Very High, $32M EAL), Strong Wind (High, $4M EAL). These account for most of the county's expected annual losses.
How does Allegheny County compare to other Pennsylvania counties?
Allegheny County ranks #2 of 67 Pennsylvania counties for overall natural disaster risk, with a high 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. Allegheny County's $354M EAL is a statistical average, not a guarantee for any specific year or address.