Sussex County, Delaware: Natural Disaster Risk and History
Sussex County, Delaware has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 94.1 out of 100, higher than about 94% of US counties, with cold waves, coastal flooding and hurricanes scoring highest of its 18 hazards and $119 million a year in expected losses.
OpenFEMA lists 18 federal disaster declarations that included Sussex County since 1965, not counting 2 for COVID-19; the latest is DR-4916-DE (Severe Winter Storm, declared 29 May 2026). NOAA's Storm Prediction Center recorded 25 tornadoes touching Sussex County from 1950 to 2025.
Live weather alerts for Delaware All official warnings Latest FEMA declarations
Population 237,214 Buildings worth $74 billion Area 1,209 sq mi Risk rank in Delaware 2 of 3 FIPS 10005
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Cold wave | Relatively High | 98.1 | $17 million | about once every 1.3 years | 12 |
| Coastal flooding | Very High | 97.6 | $14 million | about 3.7 a year | — |
| Hurricane | Relatively High | 97.2 | $35 million | about once every 5.9 years | 70 |
| Winter weather | Very High | 96.7 | $726,815 | about 7 a year | 106 |
| Inland flooding | Relatively Moderate | 92.8 | $43 million | about 2.5 a year | 71 |
| Heat wave | Relatively Moderate | 89.4 | $2.3 million | about 5 a year | 64 |
| Drought | Relatively Moderate | 86.5 | $1.1 million | about 4.3 a year | 203 |
| Strong wind | Relatively High | 85.6 | $1.3 million | about 2.4 a year | 73 |
| Wildfire | Relatively Low | 84.8 | $538,072 | rarer than once in 1,000 years | — |
| Lightning | Relatively High | 82.9 | $664,522 | about 33 a year | 252,526 strikes |
| Ice storm | Relatively Moderate | 82.1 | $385,461 | about once every 2.5 years | 23 |
| Earthquake | Relatively Low | 81.5 | $1.5 million | about once every 962 years | — |
| Tornado | Relatively Low | 63.4 | $1.6 million | about once every 2.9 years | 18 |
| Hail | Relatively Low | 60.4 | $305,691 | about once every 1.1 years | 35 |
| Landslide | Very Low | 50.6 | $1,109 | about once every 8.0 years | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Insufficient Data | — | — | — | — |
| Volcanic activity | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 18
Most common: Hurricane 6, Snowstorm 5, Severe Storm 3, Winter Storm 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 1 | Drought |
| 1990s | 6 | Severe Storm ×2, Snowstorm ×2, Coastal Storm, Flood |
| 2000s | 4 | Hurricane ×2, Severe Storm, Snowstorm |
| 2010s | 6 | Hurricane ×4, Snowstorm ×2 |
| 2020s | 1 | Winter Storm |
The last 10
Widest declarations that included Sussex County
- Hurricane Sandy (2012, DR-4090-DE): 3 Delaware counties designated.
- Hurricane Sandy (2012, EM-3357-DE): 3 Delaware counties designated.
- Hurricane Irene (2011, EM-3336-DE): 3 Delaware counties designated.
Named storms in its declarations: Hurricane Sandy (2012), Hurricane Irene (2011), Hurricane Katrina (2005), Hurricane Isabel (2003).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Delaware also had 1 statewide declaration with no county list.
Tornado record since 1950 25
| Tornadoes touching the county | 25 |
|---|---|
| Strongest-rated | (E)F3 ×1 |
| Peak month | August (7) |
| Deadliest | 1 Apr 2023, EF3, 14.3 mi path, 1 killed, 0 injured |
| Longest path | 1 Apr 2023, EF3, 14.3 mi path, 1 killed, 0 injured |
| Most recent | 30 Jun 2025, EF0, 0.5 mi path |
| Deaths / injuries on those paths | 1 / 2 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 11 | 10 | 3 | 1 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 3 | 1 | 3 | 2 | 7 | 0 | 4 | 5 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Sussex County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Sussex County (this page) | — | Relatively Moderate | 94.1 | Cold wave |
| Wicomico County, MD | 37 km | Relatively Low | 60.8 | Hurricane |
| Caroline County, MD | 44 km | Relatively Low | 45.7 | Drought |
| Worcester County, MD | 49 km | Relatively Low | 68.2 | Hurricane |
| Kent County | 49 km | Relatively Moderate | 84.5 | Cold wave |
| Dorchester County, MD | 56 km | Relatively Low | 53.8 | Coastal flooding |
Nearest by distance between county centres. Every county in Delaware, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively High 70.4 |
|---|---|
| Community resilience | Relatively Moderate 59.8 |
| Community risk factor | 1.31 |
| Expected annual loss, all hazards | $119 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Sussex County's main hazards
- Right now: National Weather Service alerts for Delaware · all official warnings on Global Incident Tracker.
- Cold wave: Carbon monoxide in winter · Power outages now
- Coastal flooding: Flood safety: why shallow water kills · Hurricanes and storms now
- Hurricane: Is there a hurricane now? · Cyclone preparation
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Sussex County
What natural disasters is Sussex County, Delaware most at risk from?
Sussex County, Delaware has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 94.1 out of 100, higher than about 94% of US counties, with cold waves, coastal flooding and hurricanes scoring highest of its 18 hazards and $119 million a year in expected losses.
How many federal disaster declarations has Sussex County had?
OpenFEMA lists 18 federal disaster declarations that included Sussex County since 1965, not counting 2 for COVID-19; the latest is DR-4916-DE (Severe Winter Storm, declared 29 May 2026). Another 1 Delaware declarations were made statewide without a county list.
How many tornadoes have hit Sussex County?
NOAA's Storm Prediction Center recorded 25 tornadoes touching Sussex County from 1950 to 2025. The deadliest: 1 Apr 2023, EF3, 14.3 mi path, 1 killed, 0 injured (deaths and injuries are for the whole path).
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.