riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Dorchester County Disaster Risk

Dorchester County, South Carolina

FEMA Risk Rating

Relatively Moderate

National Percentile

94th

of 3,144 counties

State Rank

#6

of 46 (1 = highest risk)

Flood Risk

79th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 79% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 79% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 75% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 98% of US counties

Hurricane

Tropical cyclone and hurricane risk

Relatively High

Higher than 98% of US counties

Risk Overview

About Natural Disaster Risk in Dorchester County, South Carolina

Dorchester ranks among highest-risk counties

Dorchester County scores 93.70 on the composite risk scale, placing it well above both the national average and South Carolina's state average of 70.75. Despite its relatively moderate risk rating, this is one of the most hazard-exposed counties in the state.

Dorchester is South Carolina's third riskiest

With a composite score of 93.70, Dorchester ranks in the top tier of South Carolina counties for natural disaster risk, exceeded only by a handful of peers. This high ranking reflects the county's unique geographic position near the coast and low-lying terrain.

Coastal exposure sets Dorchester apart

Dorchester's 93.70 score closely mirrors Georgetown County (92.49) and exceeds Greenville County (93.96) by a hair. Its coastal and low-lying inland areas create vulnerability to flooding, storms, and earthquake hazards that inland counties like Fairfield (40.81) simply don't face.

Flooding and hurricanes dominate Dorchester's outlook

Hurricane risk reaches 97.87 and flood risk scores 78.66, making coastal and tidal surge scenarios the top two threats to homes and infrastructure. Earthquake risk at 97.93 is also notably elevated, though less immediately predictable than weather-driven hazards.

Flood and wind coverage are non-negotiable

Dorchester residents must carry separate flood insurance and windstorm coverage, as standard policies exclude both. With hurricane and flood scores exceeding 97, the cost of insurance is far smaller than the cost of uninsured disaster losses.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Dorchester County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    98th percentile
  2. #2
    HurricanePrepare
    98th percentile
  3. #3
    WildfirePrepare
    79th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Local Resources

Risk Advisory: Dorchester County

Risk Verdict

At the 94th percentile nationally, Dorchester County sits in the upper half of U.S. counties for natural disaster exposure. At this risk level, having a documented household preparedness plan — not just awareness — is the meaningful next step for Dorchester County residents.

Hazard Breakdown

Earthquake risk is Dorchester County's dominant natural hazard, ranked at the 98th percentile nationally under FEMA's National Risk Index. Hurricane ranks second at the 98th percentile nationally. Additional tracked hazards include wildfire (79th percentile), flood (79th percentile), tornado (75th percentile).

Preparedness Context

With earthquake ranked as the top hazard at the 98th percentile nationally, Dorchester County residents benefit from reviewing homeowners insurance: standard policies rarely cover earthquake damage, and separate earthquake insurance must be purchased before an event. Hurricane at the 98th percentile nationally is a separate hazard dimension for Dorchester County that requires different protective strategies from earthquake preparedness. Earthquake insurance in Dorchester County is typically offered as a separate policy — standard homeowners coverage excludes ground movement. Reviewing this gap and comparing policy options before an event is a financial preparedness step with potentially large consequences.

Regional Context

The South Carolina county average is 23.0 composite points below Dorchester County's score, a gap that reflects the county's elevated position in the state's hazard distribution.

Is your household prepared for Dorchester County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Dorchester County, SC?
Dorchester County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 94th 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 Dorchester County?
Dorchester County is evaluated for five major natural hazard types: earthquake (98th percentile), hurricane (98th percentile), wildfire (79th percentile), flooding (79th percentile), tornado (75th percentile). The highest-risk hazard is earthquake 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 Dorchester County risk compare to the South Carolina average?
Dorchester County's composite risk percentile is 94th, compared to the South Carolina state average of 71th percentile. The state's overall risk rating is Relatively Low. This means Dorchester County faces higher natural disaster risk than the typical county in South Carolina.
Is Dorchester County at risk for earthquake?
Yes, Dorchester County's earthquake risk is at the 98th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Dorchester County is at the 79th percentile.
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 Dorchester County higher risk than average?
Dorchester County's composite risk score of 94th percentile is above the South Carolina state average of 71th percentile. This elevated risk is driven by earthquake exposure (98th percentile), along with hurricane and wildfire and flooding and tornado 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

Greenville County

South Carolina

+0.3

Relatively Moderate

94th percentile

Richland County

South Carolina

-0.6

Relatively Moderate

93th percentile

Berkeley County

South Carolina

+1.1

Relatively High

95th percentile

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, 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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