York County, SC

Supports FEMA checklist item B1-a Hazard identification

14 of the 18 National Risk Index hazards apply here.

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche, coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

Highest expected annual loss (NRI, modeled): Inland Flooding, Tornado and Cold Wave.

Not covered by NRI (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 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

• Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather: affects the whole county; national data give no location within it.
• Earthquake, Hurricane, Landslide, Tornado and Wildfire vary within the county; the packet lists the highest-rated census tracts for each.
• 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.

Supports FEMA checklist item B1-c Hazard extent

Storm Events records for 14 of the 21 NOAA event-type groups mapped to the 18 hazards, with the scale, observed range and worst recorded event for each; the others say which local data are needed.

Worst recorded tornado, hail and thunderstorm wind (the three event types on record since the 1950s; the packet has every group):

• Hail: 4 in hail, 2011-04-09; same size also recorded on 1955-04-24
• Thunderstorm Wind: 80 kt (92 mph) estimated gust, Thunderstorm Wind, 2024-04-20
• Tornado: EF2 tornado, 2011-11-16, 5.8 mi within this county, 200 yd wide, $1,000,000 property; $0 crops (2011 dollars), 3 direct deaths, 5 direct injuries

Supports FEMA checklist item B1-d Previous occurrences

Federal declarations for this area: 22 declarations covering 16 separate hazard incidents counted in this packet; each with type, dates and county Public Assistance dollars.

New since the last plan (approved 2023-01-09): EM-3632-SC, DR-4829-SC, EM-3619-SC, EM-3606-SC and EM-3597-SC.

2 statewide declarations listed separately.

Hazards with no Storm Events record and no federal declaration are stated as such (6 of 18).

Storm Events history: 759 records (notable ones in the PDF, all of them in the Excel file).

Supports FEMA checklist item B1-e Probability of future events

FEMA annualized frequency (modeled) for each hazard, with a descriptor from a scale defined in the packet.

• Highly likely: Hail, Lightning and Strong Wind
• Likely: Cold Wave, Drought, Ice Storm, Inland Flooding, Landslide, Tornado and Winter Weather
• Possible: Heat Wave and Hurricane
• Unlikely: Earthquake and Wildfire

Historical frequency by intensity band (tornado, hail, wind): 9 bands from Storm Events.

Supports FEMA checklist item B1-f Hazards that vary across jurisdictions

Range of census tract risk scores within the area for 14 of the 18 hazards (55 tracts; rated tracts only).

10 jurisdictions: plan clock, repeat-flood count, Public Assistance dollars and event records naming the place (starting figures from federal data).

County Public Assistance in B1-d also includes applicants filed under the county that are not matched to a jurisdiction row here (for example county offices and boards filed under their own names, such as a sheriff's office or a conservation board, and 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

The packet's table gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

Storm Events damage since 2023-01-09: $26,629,000 in county-coded records (38 records); $2,110,000 reported for the zone (10 zone records). Data through 2026-06-30; nominal dollars.

Local data needed

To gather:

• 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

Supports FEMA checklist item B2-a Vulnerability (county context)

Population 281,543; building value $67,406,309,385 and agriculture value $129,416,712 (total, not at risk).

National Risk Index rating Relatively Moderate; social vulnerability Very Low; community resilience Relatively High.

Supports FEMA checklist item B2-c Repetitive loss properties

Repetitive-loss properties, FMA definition (44 CFR 77.2): 0 repetitive loss, 1 severe repetitive loss. NFIP insurance definition: 4 and 1.

Mitigated 0; insured 2; NFIP data as of 2026-08-02. Counts by occupancy group and for each jurisdiction are in the packet.