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Natural hazard risk in Charleston County, South Carolina

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Relatively High (score 98.6 of 100)[5]

Expected annual loss (FEMA)
$499.8 million[1]
Federal disaster declarations since 1977
25[2]
NFIP flood claims paid, 1978 to 2026
$312.2 million[3]
Tornadoes recorded, 1950 to 2024
60[4]

FEMA's National Risk Index (version 1.20, December 2025) gives Charleston County an overall Relatively High rating, with a Risk Index score of 98.6 out of 100[5]. FEMA's highest hazard scores within the county are for coastal flooding, hurricane and earthquake[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA rates the overall natural hazard risk for Charleston County Relatively High compared with other US counties[5]. FEMA lists $499.8 million a year in Expected Annual Loss from all 18 natural hazards[1]. This is FEMA's estimate of average yearly loss, not money anyone paid[7]. By FEMA's Expected Annual Loss values, the largest are hurricane ($281.3 million a year), earthquake ($118.0 million a year), inland flooding ($44.2 million a year)[8]. FEMA rates Social Vulnerability Relatively Low[9] and Community Resilience Very High[10]. Social vulnerability describes how susceptible social groups are to harm from hazards, and community resilience describes a community's ability to prepare for, withstand and recover from them[9][10]. FEMA says the index does not predict next year's losses[7].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Coastal FloodingVery High$35.6 million[11]
HurricaneVery High$281.3 million[12]
EarthquakeRelatively High$118.0 million[13]
Ice StormRelatively High$1.8 million[14]
WildfireRelatively Moderate$3.1 million[15]
LightningRelatively High$1.7 million[16]
Inland FloodingRelatively Moderate$44.2 million[17]
Cold WaveRelatively Moderate$6.6 million[18]
Winter WeatherRelatively Moderate$301,000[19]
Heat WaveRelatively Moderate$2.0 million[20]
Strong WindRelatively Moderate$1.7 million[21]
TornadoRelatively Moderate$3.0 million[22]
HailRelatively Low$451,000[23]
LandslideVery Low$650[24]
DroughtRelatively Low$50,000[25]

Rated Not Applicable by FEMA for this county: avalanche, volcanic activity[26].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityRelatively Low22.4[9]
Community resilienceVery High96.1[10]

Flooding and flood insurance

FEMA rates coastal flooding risk Very High compared with other US counties, with a score of 99.8 out of 100[11]. FEMA rates inland flooding Relatively Moderate[17]. OpenFEMA lists 46,856 residential flood insurance contracts in force as of 2026-08-03, and 31.7% of residential structures are covered[27]. 78.3% of homes inside the SFHA are insured[27]. OpenFEMA NFIP claims data shows 19,289 claims filed for losses from 1978 to 2026, and NFIP paid $312.2 million in total[3]. To learn the flood zone of an address, use FEMA's Flood Map Service Center[28].

Measure Value
Coastal Flooding, FEMA risk rating[11] Very High, $35.6 million expected loss a year
Inland Flooding, FEMA risk rating[17] Relatively Moderate, $44.2 million expected loss a year
NFIP residential flood policies in force (2026)[27] 46,856 of 148,009 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[27] 44,952, of which 35,189 insured
NFIP flood claims, 1978 to 2026[3] 19,289 filed, $312.2 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[28]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 25 federal disaster declarations for natural hazards that include Charleston County since 1977[2]. Hurricane declarations number 16 of them[2]. The most recent is a severe winter storm declared 2026-01-23[29]. NOAA's tornado database records 60 tornadoes that touched the county from 1950 to 2024[4]. The strongest were rated F3[4].

Federal disaster declarations for natural hazards that include Charleston County, since 1977
Incident type Declarations
Hurricane[2] 16
Severe Storm[2] 3
Tropical Storm[2] 2
Severe Ice Storm[2] 1
Winter Storm[2] 1
Drought[2] 1
Flood[2] 1
Most recent declarations
Declaration Incident Declared
EM-3632-SC[29] Severe Winter Storm 2026-01-23
EM-3619-SC[29] Hurricane Helene 2024-09-26
EM-3606-SC[29] Hurricane Debby 2024-08-05
EM-3597-SC[29] Hurricane Idalia 2023-08-31
DR-4677-SC[29] Hurricane Ian 2022-11-21

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Floods

Before

  • Check your flood risk with FEMA's Flood Map Service Center, and remember that floods do not follow map lines.
  • Sign up for your community's warning system. NOAA Weather Radio also broadcasts alerts.
  • Buy flood insurance through the NFIP well before a disaster. Homeowners policies do not cover flooding, and a new policy typically takes up to 30 days to go into effect.
  • Make a household plan with evacuation routes, shelter locations and what to do in a flash flood.
  • Keep important documents in a waterproof container and make password-protected digital copies.

During

  • If you are told to evacuate, leave right away and never drive around barricades.
  • Do not walk, swim or drive through floodwater. Six inches of moving water can knock you down.
  • If you are trapped in a building, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, floods

Hurricanes

Before

  • Know your hurricane risk, including rain, wind and tornadoes far inland from landfall.
  • Learn your evacuation zone and routes, and practice them with your household and pets.
  • Keep insurance policies and ID current, with password-protected digital copies.
  • Clear drains and gutters, bring in outdoor furniture and consider hurricane shutters.
  • Keep your phone charged, buy backup chargers and gather supplies, including medication and pet supplies.

During

  • If you are in a mandatory evacuation zone and officials order an evacuation, leave right away.
  • For high winds, take shelter in a designated storm shelter or an interior room.
  • If you are trapped by flooding, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, hurricanes

Earthquakes

Before

  • Practice Drop, Cover, and Hold On with your family and coworkers.
  • Sign up for earthquake alerts that can warn you before shaking starts.
  • Make a plan with an out-of-state contact and a place to meet if you get separated.
  • Anchor heavy items such as bookcases, refrigerators and water heaters, and keep heavy things on low shelves.
  • Consider earthquake insurance. Standard homeowners policies do not cover earthquake damage.

During

  • Drop to your hands and knees, cover your head and neck, and hold on until the shaking stops.
  • Indoors, stay where you are and avoid doorways. Outdoors, move to an open area away from buildings and power lines.
  • If you are driving, pull over, stop and set the parking brake.

Source: Ready.gov, earthquakes

Questions people ask

Is Charleston County at risk of flooding?
FEMA rates coastal flooding risk Very High and inland flooding Relatively Moderate compared with other US counties[11][17]. For a specific address, check FEMA's Flood Map Service Center[28].
Is Charleston County at risk of hurricanes?
FEMA rates hurricane risk Very High compared with other US counties, with a score of 99.6 out of 100[12]. OpenFEMA lists 16 hurricane declarations that include the county since 1977[2].
Is Charleston County at risk of earthquakes?
FEMA rates earthquake risk Relatively High compared with other US counties, with a score of 98.7 out of 100[13]. FEMA lists $118.0 million a year in expected earthquake loss[13].
Does Charleston County get tornadoes?
NOAA's tornado database records 60 tornadoes that touched the county from 1950 to 2024[4]. FEMA rates tornado risk Relatively Moderate compared with other US counties[22].
How many disasters have been declared in Charleston County?
OpenFEMA lists 25 federal disaster declarations for natural hazards that include the county since 1977[2].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Charleston County is $499.8 million a year (Expected Annual Loss rating Relatively High, score 99.0). Of this, buildings account for $412.0 million, injuries and deaths (converted to dollars by FEMA) for... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 25 federal disaster declarations for natural hazards that include Charleston County since 1977 (11 major disaster, 14 emergency or fire management). By incident type: hurricane 16, severe storm 3, tropical storm 2, severe ice storm 1, winter storm 1, drought 1, flood 1.... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 19,289 National Flood Insurance Program claims were filed for losses in Charleston County, 13,284 of them with a payment, and NFIP paid $312.2 million in total (building, contents and increased cost of compliance, in dollars of the year... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 60 recorded tornadoes touched Charleston County. The strongest were rated F3 (most recent of them on 1960-09-11). 1 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2024-09-27. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Charleston County is Relatively High, with a Risk Index score of 98.6 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Charleston County are coastal flooding (99.8, Very High), hurricane (99.6, Very High), earthquake (98.7, Relatively High). HazardFacts sorted FEMA's published scores;... FEMA National Risk Index
  7. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  8. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for Charleston County (National Risk Index v1.20): the largest are hurricane ($281.3 million a year), earthquake ($118.0 million a year), inland flooding ($44.2 million a year), out of $499.8 million a year from all 18 hazards. FEMA National Risk Index
  9. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Charleston County is Relatively Low (score 22.4). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Charleston County is Very High (score 96.1). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025), coastal flooding in Charleston County: Risk Index rating Very High (score 99.8 of 100). Expected Annual Loss $35.6 million a year (rating Very High). FEMA's modeled annual frequency is 3.6472 events per year. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), hurricane in Charleston County: Risk Index rating Very High (score 99.6 of 100). Expected Annual Loss $281.3 million a year (rating Very High). Annualized frequency 0.34 events per year, from recorded occurrences over a period of record of 172 years for the... FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), earthquake in Charleston County: Risk Index rating Relatively High (score 98.7 of 100). Expected Annual Loss $118.0 million a year (rating Relatively High). FEMA's modeled annual frequency is 0.0063 events per year. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), ice storm in Charleston County: Risk Index rating Relatively High (score 94.5 of 100). Expected Annual Loss $1.8 million a year (rating Very High). Annualized frequency 0.88 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), wildfire in Charleston County: Risk Index rating Relatively Moderate (score 93.8 of 100). Expected Annual Loss $3.1 million a year (rating Relatively Moderate). FEMA's modeled annual frequency is 0.0023 events per year. FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), lightning in Charleston County: Risk Index rating Relatively High (score 92.5 of 100). Expected Annual Loss $1.7 million a year (rating Relatively High). Annualized frequency 63.33 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Charleston County: Risk Index rating Relatively Moderate (score 89.8 of 100). Expected Annual Loss $44.2 million a year (rating Relatively Moderate). Annualized frequency 3.54 event-days per year, from recorded occurrences over a period of... FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), cold wave in Charleston County: Risk Index rating Relatively Moderate (score 87.1 of 100). Expected Annual Loss $6.6 million a year (rating Relatively High). Annualized frequency 0.79 event-days per year, from recorded occurrences over a period of record of 18... FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), winter weather in Charleston County: Risk Index rating Relatively Moderate (score 84.1 of 100). Expected Annual Loss $301,000 a year (rating Relatively High). Annualized frequency 0.95 events per year, from recorded occurrences over a period of record of 18... FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), heat wave in Charleston County: Risk Index rating Relatively Moderate (score 82.6 of 100). Expected Annual Loss $2.0 million a year (rating Relatively Moderate). Annualized frequency 9.58 event-days per year, from recorded occurrences over a period of record... FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), strong wind in Charleston County: Risk Index rating Relatively Moderate (score 82.5 of 100). Expected Annual Loss $1.7 million a year (rating Relatively High). Annualized frequency 1.6 events per year, from recorded occurrences over a period of record of 38... FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), tornado in Charleston County: Risk Index rating Relatively Moderate (score 71.0 of 100). Expected Annual Loss $3.0 million a year (rating Relatively Moderate). Annualized frequency 0.49 events per year, from recorded occurrences over a period of record of 38... FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), hail in Charleston County: Risk Index rating Relatively Low (score 60.9 of 100). Expected Annual Loss $451,000 a year (rating Relatively Low). Annualized frequency 2.2 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025), landslide in Charleston County: Risk Index rating Very Low (score 37.7 of 100). Expected Annual Loss $650 a year (rating Very Low). FEMA National Risk Index
  25. FEMA National Risk Index (version 1.20, December 2025), drought in Charleston County: Risk Index rating Relatively Low (score 35.4 of 100). Expected Annual Loss $50,000 a year (rating Relatively Low). Annualized frequency 15.28 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  26. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Charleston County: avalanche, volcanic activity. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered geographically possible there. FEMA National Risk Index documentation
  27. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 46,856 residential flood insurance contracts were in force in Charleston County, out of 148,009 residential structures, a penetration rate of 31.7%. Inside FEMA's mapped Special Flood Hazard Area there were 44,952 residential structures and 35,189... OpenFEMA NFIP penetration rates
  28. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  29. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. 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). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.