New Castle County
Delaware — Natural Disaster Risk Assessment
HighComposite Risk Score
National percentile: 95th
New Castle County faces high composite natural disaster risk (NRI Risk Index score 95.3, 95th national percentile), driven primarily by winter weather and riverine flood exposure. Expected annual loss across all 18 hazard types is $202M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Winter Weather | Very High | 10.37 / yr | $2M |
| Riverine Flood | High | 6.57 / yr | $150M |
| Heat Wave | Medium | 11.16 / yr | $7M |
| Cold Wave | High | 0.79 / yr | $10M |
| Earthquake | Medium | 0.00 / yr | $9M |
| Ice Storm | High | 1.03 / yr | $913K |
| Hurricane | Medium | 0.09 / yr | $6M |
| Strong Wind | High | 6.32 / yr | $2M |
| Tornado | Medium | 0.26 / yr | $7M |
| Drought | Medium | 5.90 / yr | $1M |
| Coastal Flood | High | 3.69 / yr | $4M |
| Lightning | Medium | 35.11 / yr | $847K |
| Landslide | Low | 0.14 / yr | $12K |
| Wildfire | Very Low | 0.00 / yr | $95K |
| Hail | Very Low | 2.28 / yr | $97K |
| Avalanche | 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 New Castle County?
New Castle County has a composite FEMA National Risk Index score of 95.3 out of 100, placing it in the High category and the 95th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in New Castle County?
The three highest-rated hazards are Winter Weather (Very High, $2M EAL), Riverine Flood (High, $150M EAL), Heat Wave (Medium, $7M EAL). These account for most of the county's expected annual losses.
How does New Castle County compare to other Delaware counties?
New Castle County ranks #1 of 3 Delaware 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. New Castle County's $202M EAL is a statistical average, not a guarantee for any specific year or address.