Dorchester County, South Carolina: Natural Disaster Risk and History
Dorchester County, South Carolina has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 93.7 out of 100, higher than about 93% of US counties, with hurricanes, earthquakes and ice storms scoring highest of its 18 hazards and $176 million a year in expected losses.
OpenFEMA lists 24 federal disaster declarations that included Dorchester County since 1989, not counting 2 for COVID-19; the latest is EM-3632-SC (Severe Winter Storm, declared 23 January 2026). NOAA's Storm Prediction Center recorded 22 tornadoes touching Dorchester County from 1950 to 2025.
Live weather alerts for South Carolina All official warnings Latest FEMA declarations
Population 161,445 Buildings worth $30 billion Area 577 sq mi Risk rank in South Carolina 6 of 46 FIPS 45035
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Hurricane | Relatively High | 97.9 | $84 million | about once every 3.2 years | 102 |
| Earthquake | Relatively Moderate | 97.9 | $58 million | about once every 159 years | — |
| Ice storm | Relatively High | 83.4 | $657,559 | about 1.1 a year | 73 |
| Lightning | Relatively High | 82.7 | $1.0 million | about 66 a year | 209,176 strikes |
| Wildfire | Relatively Low | 79.0 | $454,168 | about once every 741 years | — |
| Inland flooding | Relatively Moderate | 78.7 | $23 million | about 1.4 a year | 39 |
| Tornado | Relatively Moderate | 74.8 | $3.8 million | about once every 3.1 years | 20 |
| Heat wave | Relatively Low | 69.2 | $1.1 million | about 8.9 a year | 149 |
| Winter weather | Relatively Moderate | 68.0 | $148,931 | about 1.1 a year | 20 |
| Cold wave | Relatively Moderate | 67.9 | $2.4 million | about once every 1.5 years | 13 |
| Coastal flooding | Relatively Low | 59.2 | $542,334 | about 3.5 a year | — |
| Hail | Relatively Low | 45.7 | $273,054 | about 3.1 a year | 116 |
| Drought | Very Low | 27.7 | $22,258 | about 15 a year | 469 |
| Strong wind | Relatively Low | 18.7 | $203,936 | about 3.2 a year | 123 |
| Landslide | Very Low | 14.0 | $66 | about once every 6.3 years | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| 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 24
Most common: Hurricane 15, Tropical Storm 3, Severe Storm 2, Severe Ice Storm 2.
| Decade | Declarations | Incident types |
|---|---|---|
| 1980s | 1 | Hurricane |
| 1990s | 2 | Hurricane ×2 |
| 2000s | 2 | Hurricane, Severe Storm |
| 2010s | 12 | Hurricane ×8, Severe Ice Storm ×2, Flood, Severe Storm |
| 2020s | 7 | Tropical Storm ×3, Hurricane ×3, Winter Storm |
The last 10
Widest declarations that included Dorchester County
- Severe Winter Storm (2026, EM-3632-SC): 46 South Carolina counties designated.
- Hurricane Helene (2024, EM-3619-SC): 46 South Carolina counties designated.
- Hurricane Debby (2024, EM-3606-SC): 46 South Carolina counties designated.
Named storms in its declarations: Tropical Storm Debby (2024), Hurricane Helene (2024), Hurricane Debby (2024), Hurricane Idalia (2023), Hurricane Ian (2022), Hurricane Dorian (2019), Hurricane Florence (2018), Hurricane Irma (2017), Hurricane Matthew (2016), Hurricane Katrina (2005), Hurricane Floyd (1999), Hurricane Hugo (1989).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. South Carolina also had 2 statewide declarations with no county list.
Tornado record since 1950 22
| Tornadoes touching the county | 22 |
|---|---|
| Strongest-rated | (E)F2 ×1 |
| Peak month | May (9) |
| Deadliest | 10 May 1998, F2, 10.5 mi path, 1 killed, 7 injured |
| Longest path | 10 May 1998, F2, 10.5 mi path, 1 killed, 7 injured |
| Most recent | 5 Apr 2022, EF0, 5.6 mi path |
| Deaths / injuries on those paths | 1 / 11 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 8 | 13 | 1 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 1 | 1 | 3 | 1 | 3 | 7 | 3 | 3 |
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 Dorchester County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Dorchester County (this page) | — | Relatively Moderate | 93.7 | Hurricane |
| Colleton County | 34 km | Relatively Moderate | 85.5 | Hurricane |
| Berkeley County | 44 km | Relatively High | 94.8 | Hurricane |
| Charleston County | 50 km | Relatively High | 98.6 | Coastal flooding |
| Orangeburg County | 54 km | Relatively Moderate | 87.7 | Earthquake |
| Bamberg County | 62 km | Relatively Low | 46.5 | Hurricane |
Nearest by distance between county centres. Every county in South Carolina, ranked.
Vulnerability and resilience
| Social vulnerability | Very Low 16.0 |
|---|---|
| Community resilience | Relatively Moderate 57.4 |
| Community risk factor | 0.85 |
| Expected annual loss, all hazards | $176 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 Dorchester County's main hazards
- Right now: National Weather Service alerts for South Carolina · all official warnings on Global Incident Tracker.
- Hurricane: Is there a hurricane now? · Cyclone preparation
- Earthquake: Earthquakes today · Earthquake safety guide
- Ice storm: Power outages now · Carbon monoxide in winter
- 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 Dorchester County
What natural disasters is Dorchester County, South Carolina most at risk from?
Dorchester County, South Carolina has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 93.7 out of 100, higher than about 93% of US counties, with hurricanes, earthquakes and ice storms scoring highest of its 18 hazards and $176 million a year in expected losses.
How many federal disaster declarations has Dorchester County had?
OpenFEMA lists 24 federal disaster declarations that included Dorchester County since 1989, not counting 2 for COVID-19; the latest is EM-3632-SC (Severe Winter Storm, declared 23 January 2026). Another 2 South Carolina declarations were made statewide without a county list.
How many tornadoes have hit Dorchester County?
NOAA's Storm Prediction Center recorded 22 tornadoes touching Dorchester County from 1950 to 2025. The deadliest: 10 May 1998, F2, 10.5 mi path, 1 killed, 7 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.