Williamsburg County, South Carolina Natural Disaster Risk
FEMA National Risk Index assessment · SC
MediumComposite Risk Score
National percentile: 82th
Williamsburg County faces medium composite natural disaster risk (NRI Risk Index score 82.1, 82th national percentile), driven primarily by hurricane and earthquake exposure. Expected annual loss across all 18 hazard types is $30M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Williamsburg County is medium, with a National Risk Index score of 82.1 out of 100 — placing it in the 82nd 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.
Risk here concentrates in hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at High risk — $15M in expected annual loss and about 0.30 events per year; earthquake (ground shaking from sudden movement along geologic faults) at Medium risk — $5M in expected annual loss and about 0.00 events per year; and wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $588K in expected annual loss and about 0.00 events per year. Across all hazards, FEMA estimates $30M in expected annual loss for a population of 31K.
Beyond physical exposure, Williamsburg County has a very high social vulnerability rating (how susceptible the population is to harm) and a low 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.
History supports the rating: Williamsburg County has received 30 federal disaster declarations since 1989, including 17 for hurricane events and 3 for severe storm events. The most recent was Severe Winter Storm (winter storm), declared in January 2026.
Among 46 South Carolina counties, Williamsburg County ranks #19 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Hurricane | High | 0.30 / yr | $15M |
| Earthquake | Medium | 0.00 / yr | $5M |
| Wildfire | Low | 0.00 / yr | $588K |
| Strong Wind | Medium | 3.43 / yr | $906K |
| Heat Wave | Low | 9.16 / yr | $773K |
| Ice Storm | Medium | 0.85 / yr | $188K |
| Lightning | Medium | 61.61 / yr | $373K |
| Cold Wave | Medium | 0.47 / yr | $1M |
| Riverine Flood | Low | 0.36 / yr | $6M |
| Hail | Low | 3.29 / yr | $174K |
| Drought | Low | 11.10 / yr | $68K |
| Tornado | Low | 0.51 / yr | $666K |
| Winter Weather | Low | 1.32 / yr | $29K |
| Coastal Flood | Very Low | 0.18 / yr | $734 |
| Landslide | Very Low | 0.20 / yr | $75 |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Williamsburg County has received 30 federal disaster declarations since 1989, most recently Severe Winter Storm in January 2026. Most frequent causes: Hurricane (17), Severe Storm (3), Severe Ice Storm (3).
| Declared | Type | Disaster |
|---|---|---|
| January 2026 | Winter Storm | Severe Winter Storm |
| September 2024 | Hurricane | Hurricane Helene |
| September 2024 | Tropical Storm | Hurricane Helene |
| August 2024 | Tropical Storm | Hurricane Debby |
| August 2023 | Hurricane | Hurricane Idalia |
| November 2022 | Hurricane | Hurricane Ian |
| September 2022 | Hurricane | Hurricane Ian |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2019 | Hurricane | Hurricane Dorian |
Showing the 10 most recent of 30 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Williamsburg County?
Williamsburg County has a composite FEMA National Risk Index score of 82.1 out of 100, placing it in the Medium category and the 82th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Williamsburg County?
The three highest-rated hazards are Hurricane (High, $15M EAL), Earthquake (Medium, $5M EAL), Wildfire (Low, $588K EAL). These account for most of the county's expected annual losses.
How does Williamsburg County compare to other South Carolina counties?
Williamsburg County ranks #19 of 46 South Carolina counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Williamsburg County had?
FEMA records 30 federal disaster declarations for Williamsburg County since 1989, most often 17 for hurricane events and 3 for severe storm events. The most recent was Severe Winter Storm, declared in January 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. Williamsburg County's $30M EAL is a statistical average, not a guarantee for any specific year or address.