Summary
Plan status as of 2026-09-30: Expired on 2026-07-06. Plan: Dorchester County (FEMA plan 106789), approved 2021-07-07.
Since the plan was approved on 2021-07-07: 7 new hazard declarations (5 incidents): EM-3585-SC (Hurricane Ian), DR-4677-SC (Hurricane Ian), EM-3597-SC (Hurricane Idalia), EM-3606-SC (Hurricane Debby), EM-3619-SC (Hurricane Helene), DR-4835-SC (Tropical Storm Debby), EM-3632-SC (Severe Winter Storm).
NOAA Storm Events records since that date: 137 records (data through 2026-06-30).
Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Hurricane ($84,454,200 a year), Earthquake ($58,228,131) and Inland Flooding ($22,551,047).
Repetitive-loss flood properties now: FMA RL 14, SRL 9 (44 CFR 77.2); any definition: 96.
The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.
Plan clock
- Status:
- Expired on 2026-07-06
- Plan:
- Dorchester County (FEMA plan 106789)
- Approved:
- 2021-07-07
- Days since expiry:
- 86
- Update underway:
- none recorded in FEMA's plan tracker
Until a new plan is approved, FEMA mitigation project grants (HMGP, FMA) need a FEMA exception (44 CFR 201.6(a)(3)).
What changed since your last plan (approved 2021-07-07)
- New federal declarations:
- 7 new hazard declarations (5 incidents): EM-3585-SC (Hurricane Ian), DR-4677-SC (Hurricane Ian), EM-3597-SC (Hurricane Idalia), EM-3606-SC (Hurricane Debby), EM-3619-SC (Hurricane Helene), DR-4835-SC (Tropical Storm Debby), EM-3632-SC (Severe Winter Storm)
- Storm Events records since approval:
- 137 records (data through 2026-06-30)
- Repetitive loss now:
- FMA RL 14, SRL 9 (44 CFR 77.2); any definition: 96
- Repeat-flood change:
- this release sets the baseline count.
Sources: 1, 2, 4, 6 (numbered list at the end)
Plan status for every jurisdiction listed in this county
Source: 1
| Jurisdiction | Type | Status | Plan | Approved | Expires | Days to expirynegative = days since expiry | Notes |
|---|---|---|---|---|---|---|---|
| Dorchester County (unincorporated area) | Unincorporated | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | |
| Harleyville town | Town | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | this jurisdiction approved 2021-08-23 |
| Reevesville town | Town | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | this jurisdiction approved 2023-06-14 |
| Ridgeville town | Town | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | this jurisdiction approved 2023-04-11 |
| St. George town | Town | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | this jurisdiction approved 2021-08-23 |
| Summerville town | Town | Expired on 2026-07-06 | Dorchester County (FEMA plan 106789) | 2021-07-07 | 2026-07-06 | -86 | this jurisdiction approved 2021-08-23 |
State plan status and tribal plans in this state: see the state page.
Supports FEMA checklist item B1-a: hazard identification
Hazards NRI does not cover (local data needed)
- dam failure (incl. upstream dams)
- levee failure
- flash flood as its own subtype
- ice jams
- debris flows
- erosion (riverine and coastal)
- land subsidence and sinkholes
- expansive soils
The 18 National Risk Index hazards, ranked by expected annual loss (EAL)
Sources: 5, 6
| Rank by EAL | Hazard | NRI risk rating | EAL rating | EAL buildingsmodeled dollars per year | EAL agriculturemodeled dollars per year | Cost of expected deaths and injuriesFEMA's dollar value per year, not property damage | EAL total (see note)modeled dollars per year | Storm Events records, 1996 to 2026-06-30count | Storm Events coverage note |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Hurricane | Relatively High | Very High | $77,466,722 | $651,851 | $6,335,628 | $84,454,200 | 21 | Includes 4 Tropical Depression records (outside NRI's Hurricane definition). |
| 2 | Earthquake | Relatively Moderate | Relatively High | $28,518,515 | n/a | $29,709,616 | $58,228,131 | Storm Events does not record earthquakes. | |
| 3 | Inland Flooding | Relatively Moderate | Relatively Moderate | $22,267,853 | $26,508 | $256,687 | $22,551,047 | 74 | |
| 4 | Tornado | Relatively Moderate | Relatively Moderate | $1,071,413 | $1,443 | $2,705,093 | $3,777,948 | 16 | |
| 5 | Cold Wave | Relatively Moderate | Relatively Moderate | $14,369 | $27,393 | $2,348,279 | $2,390,042 | 4 | Includes 1 Frost/Freeze record (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor). |
| 6 | Heat Wave | Relatively Low | Relatively Low | $180 | $125 | $1,081,345 | $1,081,650 | 7 | |
| 7 | Lightning | Relatively High | Relatively High | $75,374 | n/a | $939,338 | $1,014,712 | 20 | |
| 8 | Ice Storm | Relatively High | Relatively High | $537,894 | n/a | $119,665 | $657,559 | 5 | |
| 9 | Coastal Flooding | Relatively Low | Relatively Moderate | $459,619 | n/a | $82,715 | $542,334 | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). |
| 10 | Wildfire | Relatively Low | Relatively Low | $393,948 | $280 | $59,941 | $454,168 | 2 | |
| 11 | Hail | Relatively Low | Relatively Low | $13,995 | $1,989 | $257,070 | $273,054 | 165 | |
| 12 | Strong Wind | Relatively Low | Relatively Low | $31,899 | $419 | $171,618 | $203,936 | 488 | Includes 2 High Wind and 27 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition). |
| 13 | Winter Weather | Relatively Moderate | Relatively Moderate | $1,502 | $29 | $147,400 | $148,931 | 11 | |
| 14 | Drought | Very Low | Very Low | n/a | $22,258 | n/a | $22,258 | 21 | |
| 15 | Landslide | Very Low | Very Low | $65 | n/a | $1 | $66 | 0 | Declared 1 time; no Storm Events record of this type. |
Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).
NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.
Local data needed: state and local landslide records (Storm Events records this hazard only in part).
Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.
The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.
Supports FEMA checklist item B1-b: hazard location
Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.
Coastal Flooding and Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.
Hazards that vary within the county: highest-rated census tracts
Source: 5
| Hazard | Highest-rated census tractsNRI risk rating, score 0 to 100 |
|---|---|
| Earthquake | tract 107 (Very High, 99.7); tract 105.05 (Very High, 98.8); tract 108.13 (Very High, 98.7) |
| Hurricane | tract 107 (Very High, 99.9); tract 108.20 (Very High, 99.8); tract 106.03 (Very High, 99.7) |
| Landslide | tract 108.01 (Very Low, 72.6); tract 104 (Very Low, 65.4); tract 101 (Very Low, 54.1) |
| Tornado | tract 107 (Relatively High, 81.9); tract 106.03 (Relatively Moderate, 73.9); tract 108.13 (Relatively Moderate, 73.1) |
| Wildfire | tract 104 (Relatively Moderate, 94.0); tract 103.01 (Relatively Moderate, 92.6); tract 108.19 (Relatively Moderate, 92.4) |
Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 107 is Census Tract 107). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool
Supports FEMA checklist item B1-c: hazard extent
Extent: scale, observed range and worst recorded event per hazard
Sources: 6, 7
| Hazard | Scale | Recordscount and years | Observed range | Worst recorded event | Most damaging (when different) | How it applies to jurisdictions | Note |
|---|---|---|---|---|---|---|---|
| Coastal Flood, Storm Surge/Tide | none in data (flood depth: FIRM) | 0 | Flood depth: see the FEMA Flood Insurance Rate Map. | ||||
| Cold/Wind Chill, Extreme Cold/Wind Chill | wind chill | 3 records, 1996 to 2026 (3 zone-level) | 2 days to 3 days (median 2.5 days); 2 with a recorded value | 3 consecutive days, 1996-02-03 to 1996-02-05, zone-level | Countywide (zone-level records). | Wind chill: in event narratives only (local data needed). | |
| Frost/Freeze (outside NRI's Cold Wave definition) | crop damage | 1 record, 2007 (1 zone-level) | No crop damage reported in 1 record. | Countywide (zone-level records). | Temperature: in event narratives only (local data needed). | ||
| Drought | U.S. Drought Monitor scale (D0 to D4) | 21 records, 1996 to 2002 (21 zone-level) | 31 days to 214 days (median 88 days); 6 with a recorded value | 214 days (7 months), 2002-03-01 to 2002-09-30, a run of 7 consecutive Storm Events drought records, zone-level | Countywide (zone-level records). | Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only. | |
| Earthquake | Modified Mercalli (local data) | 0 | Storm Events does not record earthquakes; the USGS earthquake catalog is the source. | ||||
| Hail | hail size (inches) | 185 records, 1963 to 2025 | 0.75 in to 2.75 in (median 1 in); 185 with a recorded value | 2.75 in hail, 2012-08-02; same size also recorded on 1996-03-17 | Hail, 2011-07-01, $1,500 property; crops not reported (2011 dollars) | Event records naming jurisdictions in the plan: Summerville town (59 records), Ridgeville town (12 records), St. George town (11 records), Harleyville town (9 records), Reevesville town (6 records). | |
| Excessive Heat, Heat | heat index (in event narratives) | 7 records, 1996 to 2010 (7 zone-level) | 1 day to 31 days (median 17.5 days); 6 with a recorded value | August 1999 (1 monthly summary record), zone-level | Countywide (zone-level records). | Heat index: in event narratives only (local data needed). | |
| Hurricane, Tropical Storm, Tropical Depression | Saffir-Simpson | 21 records, 1996 to 2024 (21 zone-level) | Strongest recorded: Hurricane (Typhoon) record (NOAA's event type name), 1996-07-12, 30 kt (35 mph), measurement type not recorded, damage not reported; NWS zone SCZ044 | Most damaging recorded: Tropical Storm, 2024-09-26, $303,000 property; $0 crops, reported for the zone (2024 dollars) | Countywide (zone-level records). | Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records. | |
| Ice Storm | Sperry-Piltz ice scale (local data) | 5 records, 2002 to 2014 (5 zone-level) | No damage reported in 5 records. | Countywide (zone-level records). | Ice thickness: in event narratives only (local data needed). | ||
| Flash Flood, Flood, Lakeshore Flood | damage and flood days (flood depth: FIRM) | 74 records, 1996 to 2025 (4 zone-level) | Flash Flood, 2015-10-03, $3,093,450 property; $0 crops (2015 dollars) | Event records naming jurisdictions in the plan: Summerville town (21 records), Harleyville town (3 records), Reevesville town (2 records), Ridgeville town (1 record), St. George town (1 record). Zone-level records (4) apply countywide. | Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most. | ||
| Debris Flow | none (count and damage only) | 0 | Physical measure: in event narratives only (local data needed). | ||||
| Lightning | annualized frequency (the measure FEMA's Local Mitigation Planning Handbook names) | 20 records, 1996 to 2026 | Lightning, 2019-07-13, $100,000 property; $0 crops (2019 dollars) | Event records naming jurisdictions in the plan: Summerville town (5 records), St. George town (2 records), Ridgeville town (1 record). | Storm Events lists lightning with damage or casualties; physical measure in event narratives only (local data needed). | ||
| High Wind and Strong Wind (outside NRI's Strong Wind definition) | wind speed (kt and mph) | 29 records, 2007 to 2024 (29 zone-level) | 35 kt (40 mph) to 55 kt (63 mph) (median 40 kt (46 mph)); 29 with a recorded value | 55 kt (63 mph) estimated gust, High Wind, 2008-10-24; NWS zone SCZ044 | Strong Wind, 2007-02-25, $10,000 property; $0 crops, reported for the zone (2007 dollars) | Countywide (zone-level records). | |
| Thunderstorm Wind | wind speed (kt and mph) | 507 records, 1955 to 2026 | 40 kt (46 mph) to 91 kt (105 mph) (median 50 kt (58 mph)); 467 with a recorded value | 91 kt (105 mph) estimated gust, Thunderstorm Wind, 2020-04-13 | Thunderstorm Wind, 2008-03-15, $60,000 property; $0 crops (2008 dollars) | Event records naming jurisdictions in the plan: Summerville town (100 records), St. George town (46 records), Ridgeville town (42 records), Reevesville town (33 records), Harleyville town (25 records). | |
| Tornado | Enhanced Fujita (Fujita before Feb 2007) | 22 records, 1958 to 2022 | F/EF0 to F/EF1 (median F/EF1); 22 with a recorded value | F1 tornado, 1974-05-12, 1.5 mi path length (whole path, pre-1996), 300 yd wide, $2,500,000 property; crops not recorded (1974 dollars), 2 direct injuries | Event records naming jurisdictions in the plan: St. George town (3 records), Harleyville town (2 records), Ridgeville town (2 records), Summerville town (2 records), Reevesville town (1 record). | Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods). | |
| Wildfire | acres burned (local data) | 2 records, 2010 to 2011 (2 zone-level) | Wildfire, 2011-03-24, $500,000 property; $0 crops (2011 dollars); NWS zone SCZ044 | Countywide (zone-level records). | Acres burned: in event narratives only (local data needed). | ||
| Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet | none in data (snowfall: local data) | 11 records, 2000 to 2026 (11 zone-level) | No damage reported in 11 records. | Countywide (zone-level records). | Snow depth: in event narratives only (local data needed). |
Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records whose zone no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).
Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.
A monthly summary record covers most or all of a month; it does not count days at wave conditions.
Supports FEMA checklist item B1-d: previous occurrences
Federal declarations for this county: 26 declarations covering 14 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).
Federal disaster declarations for this county
Sources: 1, 2, 3
| Declared | Incident began | FEMA number | Type | Title | Mapped hazard | County Public Assistancefederal share obligated, nominal dollars | Flags | Notes |
|---|---|---|---|---|---|---|---|---|
| 2026-01-23 | 2026-01-21 | EM-3632-SC | Emergency | Severe Winter Storm | Winter Weather | no Public Assistance recorded | new since last plan; within last 5 years | |
| 2024-09-29 | 2024-08-04 | DR-4835-SC | Major disaster | Tropical Storm Debby | Hurricane (primary); also designated: Inland Flooding, Tornado | $901,221.44 | new since last plan; within last 5 years | |
| 2024-09-26 | 2024-09-25 | EM-3619-SC | Emergency | Hurricane Helene | Hurricane (primary); also designated: Inland Flooding, Landslide, Tornado | no Public Assistance recorded | new since last plan; within last 5 years | |
| 2024-08-05 | 2024-08-04 | EM-3606-SC | Emergency | Hurricane Debby | Hurricane (primary); also designated: Inland Flooding | no Public Assistance recorded | new since last plan; within last 5 years | same incident as DR-4835 |
| 2023-08-31 | 2023-08-29 | EM-3597-SC | Emergency | Hurricane Idalia | Hurricane (primary); also designated: Inland Flooding | $219,302.42 | new since last plan; within last 5 years | |
| 2022-11-21 | 2022-09-25 | DR-4677-SC | Major disaster | Hurricane Ian | Hurricane | $149,143.90 | new since last plan; within last 5 years | |
| 2022-09-29 | 2022-09-25 | EM-3585-SC | Emergency | Hurricane Ian | Hurricane | no Public Assistance recorded | new since last plan; within last 5 years | same incident as DR-4677 |
| 2020-03-27 | 2020-01-20 | DR-4492-SC | Major disaster | COVID-19 Pandemic | Non-natural, not counted | $126,639.06 | ||
| 2020-03-13 | 2020-01-20 | EM-3470-SC | Emergency | COVID-19 | Non-natural, not counted | no Public Assistance recorded | same incident as DR-4492 | |
| 2019-09-30 | 2019-08-31 | DR-4464-SC | Major disaster | Hurricane Dorian | Hurricane | $928,349.80 | ||
| 2019-09-01 | 2019-08-31 | EM-3421-SC | Emergency | Hurricane Dorian | Hurricane | no Public Assistance recorded | same incident as DR-4464 | |
| 2018-09-16 | 2018-09-08 | DR-4394-SC | Major disaster | Hurricane Florence | Hurricane | $268,848.32 | ||
| 2018-09-10 | 2018-09-08 | EM-3400-SC | Emergency | Hurricane Florence | Hurricane | no Public Assistance recorded | same incident as DR-4394 | |
| 2017-10-16 | 2017-09-06 | DR-4346-SC | Major disaster | Hurricane Irma | Hurricane | $98,308.87 | ||
| 2017-09-07 | 2017-09-06 | EM-3386-SC | Emergency | Hurricane Irma | Hurricane | no Public Assistance recorded | same incident as DR-4346 | |
| 2016-10-11 | 2016-10-04 | DR-4286-SC | Major disaster | Hurricane Matthew | Hurricane | $780,693.71 | ||
| 2016-10-06 | 2016-10-04 | EM-3378-SC | Emergency | Hurricane Matthew | Hurricane | no Public Assistance recorded | same incident as DR-4286 | |
| 2015-10-05 | 2015-10-01 | DR-4241-SC | Major disaster | Severe Storms and Flooding | Inland Flooding | $2,114,729.81 | ||
| 2015-10-03 | 2015-10-01 | EM-3373-SC | Emergency | Severe Storms and Flooding | Inland Flooding | no Public Assistance recorded | same incident as DR-4241 | |
| 2014-03-12 | 2014-02-10 | DR-4166-SC | Major disaster | Severe Winter Storm | Ice Storm | $3,311,588.06 | ||
| 2014-02-12 | 2014-02-10 | EM-3369-SC | Emergency | Severe Winter Storm | Ice Storm | no Public Assistance recorded | same incident as DR-4166 | |
| 2005-09-10 | 2005-08-29 | EM-3233-SC | Emergency | Hurricane Katrina Evacuation | Hurricane: evacuation support, not a local hazard event; not counted | no Public Assistance recorded | ||
| 2000-01-31 | 2000-01-22 | DR-1313-SC | Major disaster | Severe Winter Storm | Winter Weather | no Public Assistance recorded | ||
| 1999-09-21 | 1999-09-14 | DR-1299-SC | Major disaster | Hurricane Floyd Major Disaster Declarations | Hurricane | $317,843.29 | ||
| 1999-09-15 | 1999-09-14 | EM-3145-SC | Emergency | Hurricane Floyd Emergency Declarations | Hurricane | no Public Assistance recorded | same incident as DR-1299 | |
| 1989-09-22 | 1989-09-21 | DR-843-SC | Major disaster | Hurricane Hugo | Hurricane | no Public Assistance recorded |
County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.
Statewide declarations
Source: 2
| Declared | Incident began | FEMA number | Type | Title | Mapped hazard |
|---|---|---|---|---|---|
| 1955-08-20 | 1955-08-20 | DR-44-SC | Major disaster | Hurricanes | Hurricane (primary); also designated: Inland Flooding |
| 1954-10-17 | 1954-10-17 | DR-29-SC | Major disaster | Hurricane | Hurricane (primary); also designated: Inland Flooding |
FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.
Previous occurrences by hazard, with explicit no-event rows
Sources: 2, 6, 7
| Hazard | Storm Events records, all years on file(years in the Period column) | Since plan approvalrecords | In the 12 months before plan approvalrecords | Last 5 yearsrecords | Declared incidents, all yearsseparate disasters | Declared since approvalseparate disasters | Period | Statement |
|---|---|---|---|---|---|---|---|---|
| Coastal Flooding | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Cold Wave | 4 | 2 | 0 | 2 | 0 | 0 | 1996 to 2026-06-30 | Includes 1 Frost/Freeze record. |
| Drought | 21 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Earthquake | 0 | 0 | 0 | 0 | 0 | 0 | Storm Events does not record earthquakes; the USGS earthquake catalog is the source. | |
| Hail | 185 | 14 | 6 | 13 | 0 | 0 | 1955 to 2026-06-30 | |
| Heat Wave | 7 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Hurricane | 21 | 4 | 0 | 4 | 10 | 4 | 1996 to 2026-06-30 | Includes 4 Tropical Depression records. |
| Ice Storm | 5 | 0 | 0 | 0 | 1 | 0 | 1996 to 2026-06-30 | |
| Inland Flooding | 74 | 19 | 1 | 19 | 4 | 3 | 1996 to 2026-06-30 | |
| Landslide | 0 | 0 | 0 | 0 | 1 | 1 | 1996 to 2026-06-30 | No Storm Events records of this type; 1 federal declared incident (see declarations table) |
| Lightning | 20 | 5 | 0 | 4 | 0 | 0 | 1996 to 2026-06-30 | |
| Strong Wind | 536 | 86 | 3 | 86 | 0 | 0 | 1955 to 2026-06-30 | Includes 2 High Wind and 27 Strong Wind records. |
| Tornado | 22 | 1 | 1 | 1 | 2 | 2 | 1950 to 2026-06-30 | |
| Wildfire | 2 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Winter Weather | 11 | 6 | 0 | 6 | 2 | 1 | 1996 to 2026-06-30 |
Notable Storm Events records
Sources: 1, 6, 7
| Date | Event type | Magnitude or extent | Damagenominal dollars | Deaths, injuriesdirect only | Location | Flags | Why listed |
|---|---|---|---|---|---|---|---|
| 2025-01-10 | Winter Weather | property not reported; $0 crops, reported for the zone (2025 dollars) | 0, 2 | NWS zone SCZ044 (DORCHESTER), zone-level | new since last plan; within last 5 years | deaths or injuries recorded | |
| 2020-04-13 | Thunderstorm Wind | 91 kt (105 mph) estimated gust | damage not reported | 0, 0 | GIVHANS | B1-c worst recorded: Thunderstorm Wind | |
| 2019-07-13 | Lightning | $100,000 property; $0 crops (2019 dollars) | 0, 0 | RIDGEVILLE | B1-c worst recorded: Lightning | ||
| 2015-10-03 | Flash Flood | $3,093,450 property; $0 crops (2015 dollars) | 0, 0 | SUMMERVILLE MEML ARP to SLANDSVILLE | B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood | ||
| 2012-08-02 | Hail | 2.75 in | $0 property; $0 crops (2012 dollars) | 0, 0 | GIVHANS | B1-c worst recorded: Hail | |
| 2011-03-24 | Wildfire | $500,000 property; $0 crops, reported for the zone (2011 dollars) | 0, 0 | NWS zone SCZ044 (DORCHESTER), zone-level | B1-c worst recorded: Wildfire | ||
| 2008-10-24 | High Wind | 55 kt (63 mph) estimated gust | $1,500 property; $0 crops, reported for the zone (2008 dollars) | 0, 0 | NWS zone SCZ044 (DORCHESTER), zone-level | B1-c worst recorded: High Wind and Strong Wind | |
| 1999-08-01 | Heat | damage not reported | 0, 0 | NWS zone SCZ044 (DORCHESTER), zone-level | B1-c worst recorded: Excessive Heat, Heat | ||
| 1996-07-12 | Hurricane (Typhoon), NOAA's event type name | damage not reported | 0, 0 | NWS zone SCZ044 (DORCHESTER), zone-level | B1-c worst recorded: Hurricane, Tropical Storm, Tropical Depression | ||
| 1996-02-03 | Cold/Wind Chill | damage not reported | 0, 0 | NWS zone SCZ044 (DORCHESTER), zone-level | B1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill | ||
| 1995-07-07 | Thunderstorm Wind | speed not recorded | $50,000 property; crops not recorded (1995 dollars) | 0, 4 | Summerville | deaths or injuries recorded | |
| 1974-05-12 | Tornado | F1, 1.5 mi path length (whole path, pre-1996), 300 yd wide | $2,500,000 property; crops not recorded (1974 dollars) | 0, 2 | location not recorded | deaths or injuries recorded |
The full list is in the Excel file, sheet "B1-d Storm Events history" (908 rows).
Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.
Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).
Tribal and special-area declarations in this state are listed on the state page.
Supports FEMA checklist item B1-e: probability of future events
Probability: FEMA annualized frequency and descriptor per hazard
Sources: 5, 6
| Hazard | FEMA annualized frequency (modeled)unit per row | Unit | In plain terms | Descriptor | Descriptor basis | NRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional) | NRI period | Location | Note |
|---|---|---|---|---|---|---|---|---|---|
| Coastal Flooding | 3.5 | events per year at a location (modeled) | about 3.5 per year at a given location in the county | Highly likely | FEMA annualized frequency (modeled) | not shown | modeled | see B1-f | Descriptor from NRI: the rate at a location is 1 or more a year, so the county rate is at least that. |
| Cold Wave | 0.685 | event-days per year | about 0.685 days per year | Possible (from Storm Events: 1 of 30 years) | event-days in 1 of 30 years, 1996 to 2025 (3.33%) | 13 | 2005-11-12 to 2024-11-12 (19 years) | countywide | |
| Drought | 15.4 | event-days per year | about 15.4 days per year | Likely (from Storm Events: 5 of 30 years) | event-days in 5 of 30 years, 1996 to 2025 (16.7%) | 469 | 2000 to 2025 (25.25 years; D3 and D4 only) | countywide | |
| Earthquake | 0.00629 | annual probability at a location | chance a given location in the county has at least minor-damage shaking in a year: 0.629% | not shown | modeled | see B1-f | No descriptor (Storm Events does not record earthquakes). | ||
| Hail | 3.05 | events per year | about 3.05 per year | Highly likely | FEMA annualized frequency (modeled) | 115.7 (modeled) | 1986 to 2023 (38 years) | countywide | |
| Heat Wave | 8.91 | event-days per year | about 8.91 days per year | Likely (from Storm Events: 6 of 30 years) | event-days in 6 of 30 years, 1996 to 2025 (20%) | 149 | 2005-11-12 to 2024-11-12 (19 years) | countywide | |
| Hurricane | 0.314 | events per year | about 1 in 3 years | Likely | FEMA annualized frequency (modeled) | 102 | 1851 to 2024 (Atlantic) | see B1-f | NRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d. |
| Ice Storm | 1.09 | event-days per year | about 1.09 days per year | Likely (from Storm Events: 4 of 30 years) | event-days in 4 of 30 years, 1996 to 2025 (13.3%) | 73 | 1946-12-31 to 2014-02-12 (67 years) | countywide | |
| Inland Flooding | 1.39 | event-days per year | about 1.39 days per year | Likely (from Storm Events: 22 of 30 years) | event-days in 22 of 30 years, 1996 to 2025 (73.3%) | 39 | 1996 to 2023 (28 years) | see B1-f | |
| Landslide | 0.16 | events per year (modeled) | about 1 in 6 years | Likely | FEMA annualized frequency (modeled) | not shown | modeled | see B1-f | |
| Lightning | 66.1 | days per year with a strike | about 66.1 days per year | Highly likely | FEMA annualized frequency (modeled) | not shown | 1995 to 2023 (29 years; CONUS) | countywide | |
| Strong Wind | 3.21 | events per year | about 3.21 per year | Highly likely | FEMA annualized frequency (modeled) | 123 | 1986 to 2023 (38 years) | countywide | |
| Tornado | 0.325 | events per year | about 1 in 3 years | Likely | FEMA annualized frequency (modeled) | not shown | 1950 to 2023 (EF2+); 1986 to 2023 (EF0-1) | see B1-f | |
| Wildfire | 0.00135 | annual probability at a location | chance a given location in the county burns in a year: 0.135% | Possible (from Storm Events: 2 of 30 years) | Storm Events records in 2 of 30 years, 1996 to 2025 (6.67%) | not shown | modeled | see B1-f | Descriptor from Storm Events, not NRI. |
| Winter Weather | 1.05 | event-days per year | about 1.05 days per year | Likely (from Storm Events: 6 of 30 years) | event-days in 6 of 30 years, 1996 to 2025 (20%) | 20 | 2005-11-12 to 2024-11-12 (19 years) | countywide |
FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.
Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.
Descriptor scale used in this packet (defined per unit)
Sources: 5, 6
| Unit | Descriptor | Definition |
|---|---|---|
| events per year | Highly likely | 1 or more per year |
| events per year | Likely | about once in 1 to 10 years |
| events per year | Possible | about once in 10 to 100 years |
| events per year | Unlikely | less than once in 100 years |
| annual probability | Likely | 10% to under 100% chance in a given year |
| annual probability | Possible | 1% to under 10% chance in a given year |
| annual probability | Unlikely | under 1% chance in a given year |
| event-days (share of years) | Highly likely | event-days recorded in 90% or more of years |
| event-days (share of years) | Likely | event-days recorded in 10% to under 90% of years |
| event-days (share of years) | Possible | event-days recorded in some years but under 10% of years |
| lightning strike-days | Highly likely | cloud-to-ground strikes on 1 or more days per year |
Intensity bands: historical frequency (Storm Events)
Source: 6
| Hazard | Band | Years | Eventscounty-coded records | Years in period | Events per yearevents / years |
|---|---|---|---|---|---|
| Hail | 1.00-1.99 in | 1996 to 2025 | 86 | 30 | 2.87 |
| Hail | 2.00 in+ | 1996 to 2025 | 4 | 30 | 0.133 |
| Thunderstorm Wind (counted as NRI Strong Wind) | 50-64 kt | 1996 to 2025 | 413 | 30 | 13.8 |
| Thunderstorm Wind (counted as NRI Strong Wind) | 65 kt+ | 1996 to 2025 | 11 | 30 | 0.367 |
| Thunderstorm Wind (counted as NRI Strong Wind) | unmeasured or below 50 kt | 1996 to 2025 | 29 | 30 | 0.967 |
| Tornado | EF0-1 | 1996 to 2025 | 16 | 30 | 0.533 |
| Tornado | EF2-3 | 1996 to 2025 | 0 | 30 | 0 |
| Tornado | EF4-5 | 1996 to 2025 | 0 | 30 | 0 |
| Tornado | unrated (EFU) | 1996 to 2025 | 0 | 30 | 0 |
The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).
Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.
Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions (https://resilience.climate.gov/).
Supports FEMA checklist item B1-f: hazards that vary across jurisdictions
Range of census tract risk within the county
Source: 5
| Hazard | Tractsrated of all | NRI risk score, 0 to 100 | Tracts by rating | ||
|---|---|---|---|---|---|
| Min | Median | Max | |||
| Coastal Flooding | 20 of 31 | 69.9 | 79.6 | 98.0 | Relatively High 2, Relatively Moderate 3, Relatively Low 10, Very Low 5, No Rating 11 |
| Cold Wave | 31 of 31 | 32.6 | 58.4 | 74.8 | Relatively Moderate 25, Relatively Low 6 |
| Drought | 17 of 31 | 67.1 | 70.1 | 88.1 | Relatively Low 5, Very Low 12, No Rating 14 |
| Earthquake | 31 of 31 | 79.4 | 93.4 | 99.7 | Very High 7, Relatively High 15, Relatively Moderate 9 |
| Hail | 31 of 31 | 32.7 | 51.6 | 66.5 | Relatively Low 28, Very Low 3 |
| Heat Wave | 31 of 31 | 13.2 | 44.0 | 66.2 | Relatively Moderate 6, Relatively Low 22, Very Low 3 |
| Hurricane | 31 of 31 | 91.5 | 98.3 | 99.9 | Very High 23, Relatively High 8 |
| Ice Storm | 31 of 31 | 50.0 | 81.7 | 94.0 | Relatively High 4, Relatively Moderate 23, Relatively Low 4 |
| Inland Flooding | 31 of 31 | 3.5 | 56.4 | 91.2 | Relatively High 5, Relatively Moderate 12, Relatively Low 10, Very Low 4 |
| Landslide | 22 of 31 | 8.7 | 30.9 | 72.6 | Very Low 22, No Rating 9 |
| Lightning | 31 of 31 | 43.8 | 80.5 | 94.1 | Relatively High 16, Relatively Moderate 13, Relatively Low 2 |
| Strong Wind | 31 of 31 | 12.6 | 24.8 | 49.2 | Relatively Low 24, Very Low 7 |
| Tornado | 31 of 31 | 38.6 | 59.7 | 81.9 | Relatively High 1, Relatively Moderate 24, Relatively Low 6 |
| Wildfire | 31 of 31 | 54.3 | 80.9 | 94.0 | Relatively Moderate 8, Relatively Low 17, Very Low 6 |
| Winter Weather | 31 of 31 | 37.3 | 62.9 | 78.8 | Relatively High 1, Relatively Moderate 26, Relatively Low 4 |
Drought: Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range mostly reflects where crop and livestock value is.
Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.
The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.
Frequency data for cold wave, drought, hail, heat wave, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are (crop and livestock value where a line above names agriculture).
Each jurisdiction (starting figures from federal data)
Sources: 1, 3, 4, 6
| Jurisdiction | Type | Plan status | Repetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definition | Public Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollars | Event records naming this placeall years; since its plan | Notes |
|---|---|---|---|---|---|---|
| Dorchester County (unincorporated area) | Unincorporated | Expired on 2026-07-06 | FMA RL 9, SRL 8; any 76 | $6,300,041.02 | 0 total; 0 since its plan | Includes $114,447.78 for declarations not counted as hazard incidents (DR-4492-SC). |
| Harleyville town | Town | Expired on 2026-07-06 | FMA RL 0, SRL 0; any 0 | $60,780.80 | 39 total; 4 since its plan | |
| Reevesville town | Town | Expired on 2026-07-06 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 42 total; 9 since its plan | |
| Ridgeville town | Town | Expired on 2026-07-06 | FMA RL 0, SRL 0; any 0 | $4,604.78 | 58 total; 3 since its plan | |
| St. George town | Town | Expired on 2026-07-06 | FMA RL 0, SRL 0; any 0 | $208,405.25 | 63 total; 6 since its plan | |
| Summerville town | Town | Expired on 2026-07-06 | FMA RL 5, SRL 1; any 17 | $683,538.49 | 187 total; 16 since its plan | Includes $4,387 for declarations not counted as hazard incidents (DR-4492-SC). |
Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).
County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.
Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts
Local data needed
The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.
- Critical facilities and lifelines per hazard
- A problem statement per jurisdiction per hazard
- Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
- Future assets
County-level starter: exposure, expected annual loss and damage since the plan
Sources: 1, 2, 3, 5, 6, 7
| Hazard | Building exposuremodeled dollars | Agriculture exposuremodeled dollars | Population exposedpeople | EAL buildingsmodeled dollars per year | EAL agriculturemodeled dollars per year | Cost of expected deaths and injuriesFEMA's dollar value per year, not property damage | EAL as % of exposurebuildings; agriculture where noted | Storm Events damage since 2021-07-07county-coded records, property plus crops, nominal dollars | Zone-level damage since planproperty plus crops, reported for the zone | Public Assistance since plannominal dollars; see note | Note |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Coastal Flooding | $2,863,529,380 | n/a | 14,203 | $459,619 | n/a | $82,715 | 0.0161% | ||||
| Cold Wave | $29,984,495,069 | $51,429,342 | 161,445 | $14,369 | $27,393 | $2,348,279 | under 0.0001% | $0 | |||
| Drought | n/a | $14,916,801 | n/a | n/a | $22,258 | n/a | 0.149% (agriculture) | NRI has no building exposure for this hazard; agriculture shown | |||
| Earthquake | $49,446,938,645 | n/a | 161,540 | $28,518,515 | n/a | $29,709,616 | 0.0577% | ||||
| Hail | $29,984,495,069 | $51,429,342 | 161,445 | $13,995 | $1,989 | $257,070 | under 0.0001% | $0 | |||
| Heat Wave | $29,984,495,069 | $51,429,342 | 161,445 | $180 | $125 | $1,081,345 | under 0.0001% | ||||
| Hurricane | $29,982,865,530 | $51,429,342 | 161,432 | $77,466,722 | $651,851 | $6,335,628 | 0.258% | $303,000 | $1,269,667.76 | ||
| Ice Storm | $29,984,491,932 | n/a | 161,445 | $537,894 | n/a | $119,665 | 0.00179% | ||||
| Inland Flooding | $29,969,538,750 | $1,476,925 | 8,755 | $22,267,853 | $26,508 | $256,687 | n/a (see note) | $270,000 | $1,120,523.86 | NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b. | |
| Landslide | $7,468,115 | n/a | 36 | $65 | n/a | $1 | 0.000873% | no Public Assistance recorded (1 declaration) | |||
| Lightning | $29,984,495,069 | n/a | 161,445 | $75,374 | n/a | $939,338 | 0.000251% | $107,000 | |||
| Strong Wind | $29,984,495,069 | $51,429,342 | 161,445 | $31,899 | $419 | $171,618 | 0.000106% | $22,250 | $3,000 | Storm Events damage since the plan includes 2 zone-level Strong Wind records ($3,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition. | |
| Tornado | $29,984,495,069 | $51,429,342 | 161,445 | $1,071,413 | $1,443 | $2,705,093 | 0.00357% | $901,221.44 | |||
| Wildfire | $4,191,385,254 | $24,514,879 | 36,502 | $393,948 | $280 | $59,941 | 0.0094% | ||||
| Winter Weather | $29,984,495,069 | $51,429,342 | 161,445 | $1,502 | $29 | $147,400 | under 0.0001% | $0 | no Public Assistance recorded (1 declaration) |
Totals since 2021-07-07 (Storm Events through 2026-06-30): 118 county-coded records, 72 with a damage value recorded (including $0), $399,250; 19 zone-level records, 14 with a damage value recorded (including $0), $306,000 reported for the zone; Public Assistance: $1,269,667.76 on 7 counted declarations, 3 of them with Public Assistance.
FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.
NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.
Supports FEMA checklist item B2-a: vulnerability (county context)
County context
Source: 5
| Measure | Value |
|---|---|
| Population | 161,445 |
| Building value (total, not at risk) | $29,984,495,069 |
| Agriculture value (total, not at risk) | $51,429,342 |
| NRI risk rating (all hazards) | Relatively Moderate |
| Expected annual loss, buildings and agriculture, all hazards | $131,585,642 |
| Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage) | $44,214,395 |
| Social vulnerability rating | Very Low |
| Community resilience rating | Relatively Moderate |
| NRI version | December 2025 |
FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.
Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.
Supports FEMA checklist item B2-c: repetitive loss properties
Repetitive loss in this county, both definitions
Sources: 1, 4
| Definition | Properties | Severe repetitive loss | Properties |
|---|---|---|---|
| Repetitive loss, FMA definition (44 CFR 77.2) | 14 | Severe repetitive loss, FMA definition (44 CFR 77.2) | 9 |
| Repetitive loss, NFIP insurance definition | 96 | Severe repetitive loss, NFIP insurance definition | 9 |
The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).
Repeat-flood properties: county and state-level rows
Sources: 1, 4
| Scope | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties |
|---|---|---|---|---|---|---|---|
| County total | 14 | 9 | 96 | 9 | 96 | 0 | 62 |
| of which: North Charleston city (plan jurisdiction listed on the Charleston County page) | 0 | 0 | 3 | 0 | 3 | 0 | 2 |
| of which: Dorchester County (unincorporated area) | 9 | 8 | 76 | 8 | 76 | 0 | 47 |
| of which: Summerville town | 5 | 1 | 17 | 1 | 17 | 0 | 13 |
| Statewide, no county in FEMA's file | 0 | 0 | 2 | 0 | 2 | 0 | 0 |
3 of the county's repeat-flood properties belong to NFIP communities whose plan jurisdiction is not listed on this page (the community rows above name the page that lists it).
The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.
Repeat-flood properties by jurisdiction in the plan (NFIP community)
Sources: 1, 4
| Jurisdiction | NFIP community ID | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties |
|---|---|---|---|---|---|---|---|---|
| Dorchester County (unincorporated area) | 450068 | 9 | 8 | 76 | 8 | 76 | 0 | 47 |
| Harleyville town | 450070 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Reevesville town | 450218 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ridgeville town | 450071 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| St. George town | 450072 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Summerville town | 450073 | 5 | 1 | 17 | 1 | 17 | 0 | 13 |
Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".
Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.
County repeat-flood properties by occupancy group
Sources: 1, 4
| Occupancy group | RL, FMAproperties | SRL, FMAproperties | RL, NFIPproperties | SRL, NFIPproperties | Any categoryproperties | Mitigatedproperties | Currently insuredproperties |
|---|---|---|---|---|---|---|---|
| single-family residential | 14 | 9 | 87 | 9 | 87 | 0 | 58 |
| 2 to 4 unit residential | 0 | 0 | 2 | 0 | 2 | 0 | 1 |
| other residential | 0 | 0 | 3 | 0 | 3 | 0 | 3 |
| non-residential | 0 | 0 | 4 | 0 | 4 | 0 | 0 |
| not reported | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.
FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.
Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.
In this county 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 82 properties are NFIP repetitive loss but not FMA repetitive loss.
Exact counts; no count suppression.
Sources
Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):
- FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
- FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
- FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
- FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
- FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
- NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
- NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
- U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)
What this packet is and what the plan adds
This packet is the federal data for the plan's risk assessment, organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B. Each section heading names the item its tables support; the plan and FEMA's review decide whether the item is met.
The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.
How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.
OpenFEMA disclaimer
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).
Reuse, citation and corrections
Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.
Cite this: Hazard Plain (2026). Dorchester County, SC: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 45035). Automated baseline. https://hazardplain.org/sc/45035/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.
Corrections: to report an error, name the packet, the table and what your records show. Contact: [email protected]
Hazard Plain release 2026-10. As of 2026-09-30; Storm Events data through 2026-06-30. Automated baseline.