Sussex County, Delaware Natural Disaster Risk
FEMA National Risk Index assessment · DE
MediumComposite Risk Score
National percentile: 94th
Sussex County faces medium composite natural disaster risk (NRI Risk Index score 94.1, 94th national percentile), driven primarily by cold wave and coastal flood exposure. Expected annual loss across all 18 hazard types is $119M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Sussex County carries a medium composite natural disaster risk, with a National Risk Index score of 94.1 out of 100 — placing it in the 94th national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Sussex County's expected losses come from cold wave (prolonged spells of dangerously low temperatures) at High risk — $17M in expected annual loss and about 0.79 events per year; coastal flood (seawater inundation from storm surge, high tides, and rising sea levels) at Very High risk — $14M in expected annual loss and about 3.65 events per year; and hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at High risk — $35M in expected annual loss and about 0.17 events per year. Across all hazards, FEMA estimates $119M in expected annual loss for a population of 237K.
Beyond physical exposure, Sussex County has a high social vulnerability rating (how susceptible the population is to harm) and a medium community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
The federal record bears this out: Sussex County has received 20 federal disaster declarations since 1965, including 6 for hurricane events and 5 for snowstorm events. The most recent was Severe Winter Storm (winter storm), declared in May 2026.
Among 3 Delaware counties, Sussex County ranks #2 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 0.79 / yr | $17M |
| Coastal Flood | Very High | 3.65 / yr | $14M |
| Hurricane | High | 0.17 / yr | $35M |
| Winter Weather | Very High | 7.03 / yr | $727K |
| Riverine Flood | Medium | 2.54 / yr | $43M |
| Heat Wave | Medium | 5.03 / yr | $2M |
| Drought | Medium | 4.26 / yr | $1M |
| Strong Wind | High | 2.36 / yr | $1M |
| Wildfire | Low | 0.00 / yr | $538K |
| Lightning | High | 32.75 / yr | $665K |
| Ice Storm | Medium | 0.40 / yr | $385K |
| Earthquake | Low | 0.00 / yr | $2M |
| Tornado | Low | 0.34 / yr | $2M |
| Hail | Low | 0.92 / yr | $306K |
| Landslide | Very Low | 0.13 / yr | $1K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Sussex County has received 20 federal disaster declarations since 1965, most recently Severe Winter Storm in May 2026. Most frequent causes: Hurricane (6), Snowstorm (5), Severe Storm (3).
| Declared | Type | Disaster |
|---|---|---|
| May 2026 | Winter Storm | Severe Winter Storm |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2016 | Snowstorm | Severe Winter Storm and Snowstorm |
| November 2012 | Hurricane | Hurricane Sandy |
| October 2012 | Hurricane | Hurricane Sandy |
| September 2011 | Hurricane | Hurricane Irene |
| August 2011 | Hurricane | Hurricane Irene |
| March 2010 | Snowstorm | Severe Winter Storms and Snowstorms |
| July 2006 | Severe Storm | Severe Storms and Flooding |
Showing the 10 most recent of 20 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Sussex County?
Sussex County has a composite FEMA National Risk Index score of 94.1 out of 100, placing it in the Medium category and the 94th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Sussex County?
The three highest-rated hazards are Cold Wave (High, $17M EAL), Coastal Flood (Very High, $14M EAL), Hurricane (High, $35M EAL). These account for most of the county's expected annual losses.
How does Sussex County compare to other Delaware counties?
Sussex County ranks #2 of 3 Delaware counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Sussex County had?
FEMA records 20 federal disaster declarations for Sussex County since 1965, most often 6 for hurricane events and 5 for snowstorm events. The most recent was Severe Winter Storm, declared in May 2026.
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. Sussex County's $119M EAL is a statistical average, not a guarantee for any specific year or address.