riskbycounty
FEMA National Risk Index

New Castle County Disaster Risk

New Castle County, Delaware

FEMA Risk Rating

Relatively High

National Percentile

95th

of 3,144 counties

State Rank

#1

of 3 (1 = highest risk)

Flood Risk

98th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively High

Higher than 98% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 61% of US counties

Tornado

Tornado and severe thunderstorm risk

Moderate

Higher than 88% of US counties

Earthquake

Seismic activity and ground shaking risk

Moderate

Higher than 93% of US counties

Hurricane

Tropical cyclone and hurricane risk

Moderate

Higher than 88% of US counties

Risk Advisory: New Castle County

Risk Verdict

New Castle County carries a relatively high overall disaster risk profile, scoring in the 95th percentile nationally. This places it among the most at-risk counties in the United States. Residents should prioritize comprehensive emergency preparedness, including reviewing insurance coverage and having an evacuation plan.

Hazard Breakdown

Flood risk is the dominant hazard for New Castle County, scoring in the 98th percentile nationally. It is followed by earthquake risk at the 93th percentile. Additional hazards include hurricane (88th), tornado (88th), wildfire (61th).

Preparedness Context

With flood risk as the top concern, New Castle County residents should review flood insurance needs (standard home insurance does not cover flood damage), know your evacuation zone, and keep important documents waterproofed. Secondary risks such as earthquake also warrant attention in household and community preparedness planning. FEMA recommends all households maintain at least 72 hours of food, water, and medication supplies regardless of specific hazard exposure.

Regional Context

New Castle County has a disaster risk profile close to the average county in Delaware. Its composite risk score is within 4 points of the state average, meaning its overall hazard exposure is broadly representative of Delaware as a whole.

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Frequently Asked Questions

What is the natural disaster risk in New Castle County, DE?
New Castle County has a FEMA National Risk Index rating of Relatively High, placing it in the 95th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect New Castle County?
New Castle County is evaluated for five major natural hazard types: flooding (98th percentile), earthquake (93th percentile), hurricane (88th percentile), tornado (88th percentile), wildfire (61th percentile). The highest-risk hazard is flooding at the 98th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does New Castle County risk compare to the Delaware average?
New Castle County's composite risk percentile is 95th, compared to the Delaware state average of 91th percentile. The state's overall risk rating is Relatively Moderate. This means New Castle County faces higher natural disaster risk than the typical county in Delaware.
Is New Castle County at risk for flooding?
Yes, New Castle County's flooding risk is at the 98th percentile nationally. This places it in the top quartile for this hazard type.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is New Castle County higher risk than average?
New Castle County's composite risk score of 95th percentile is above the Delaware state average of 91th percentile. This elevated risk is driven by flooding exposure (98th percentile), along with earthquake and hurricane and tornado and wildfire risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Sussex County

Delaware

-1.1

Relatively Moderate

94th percentile

Kent County

Delaware

-10.8

Relatively Moderate

85th percentile

By Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.

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