Sullivan's Island, SC land: flood and parcels

Acres on the roll: County tax roll, counted on our map built Oct 17, 2026.

In a FEMA flood zone: FEMA National Flood Hazard Layer, as of Sep 27, 2026; counted on our map built Oct 17, 2026.

South Carolina Code of Laws 12-45-70, 12-45-180 and 12-60-2510. Checked Oct 20, 2026.

FEMA flood zone (A or V): FEMA National Flood Hazard Layer, as of Sep 27, 2026; counted on our map built Oct 17, 2026.

Parcels at least 25% wetland: USFWS National Wetlands Inventory, as of Oct 1, 2026; counted on our map built Oct 17, 2026.

Area statistics for buildings with NFIP flood insurance, not any one parcel: a lot that never had an insured building has no claims to count. Claims counted from 1978 to Sep 2026.

Source: OpenFEMA NFIP Redacted Claims v3, as of Sep 2026.

Middle half: the middle half of premiums on single-family NFIP policies that took effect Sep 2025–Sep 2026, by the flood zone each policy is rated in. It is what insured homes here pay, not a quote for any one building.

Full-risk median: the median of FEMA's own full-risk premium for the same policies (Risk Rating 2.0). A discounted policy rises toward it a step each year, within the law's cap on yearly increases.

Source: OpenFEMA NFIP Redacted Policies v3, as of Sep 2026.

Counted in the 1 census block group that lies mostly inside Sullivan's Island, so the edges may reach past the town line.

Hurricanes and tropical storms: the National Hurricane Center's final storm tracks for the 1950–2025 seasons. A storm counts when its center came within 50 miles of Sullivan's Island's limits (its Census place boundary). NHC records a storm's position every six hours; the path between those points is filled in with straight steps every ten minutes. A storm counts as a hurricane if it was one (winds of 74 mph or more) while within 50 miles, otherwise as a tropical storm (39 mph or more; subtropical storms included). A storm that had already lost its tropical status is not counted. A storm's status (hurricane, tropical storm or neither) holds until NHC's next position records a change. The category is the Saffir-Simpson category at the storm's highest wind within 50 miles.

Tornadoes: the Storm Prediction Center's tornado records, 1950–2025. Each tornado counts once for a county when SPC lists that county for it or its recorded path (a straight line from touchdown to lift-off) crosses the county. Ratings use the Fujita scale (F) before February 2007 and the Enhanced Fujita scale (EF) since; tornadoes with no rating are left out of the rating figures.

These are counts of past storms, not a forecast. They are a different measure from federal disaster declarations, which name every county a storm affected, wherever its center went.

Sources: NOAA National Hurricane Center, HURDAT2 best tracks (Atlantic and Northeast Pacific files, through 2025); NOAA Storm Prediction Center, Severe Weather Database (tornadoes) (through 2025). Public domain.

This tracks home values, not land values. Land buyers read it as a sign of demand nearby: where homes gain value, builders and buyers follow. A vacant lot can move differently.

How: the change in FHFA's annual county index from 2020 and 2024 to 2025, rounded. The index follows repeat sales and refinance appraisals of the same single-family homes with Fannie Mae or Freddie Mac mortgages. It is in today's dollars, not adjusted for inflation, and FHFA calls these local indexes developmental. Where FHFA's sample is too small it publishes no figure, and none prints here.

Source: FHFA House Price Index, all-transactions, annual county index, 2025, last updated March 31, 2026. Method: Bogin, Doerner and Larson, “Local House Price Dynamics: New Indices and Stylized Facts”, FHFA Working Paper 16-01.

FHFA publishes no index for Sullivan's Island itself; this is Charleston County's, which includes it.

Counted inside the Census place boundary of Sullivan's Island town. Counted from USGS Annual NLCD land cover (2015, 2020 and 2025; 30 m squares on a 240 m grid, so edges are approximate). A square counts when it was forest, shrub, grassland, pasture, cropland or wetland in the start year and developed in 2025 (NLCD's developed classes, from lawns and roads to dense buildings). A satellite land-cover map misses some changes and mislabels a few; read it as a guide.

Source: USGS Annual NLCD Collection 1.2, public domain, DOI 10.5066/P94UXNTS.

How: the frost dates are NOAA's 50% dates for 32°F: in half of the years 1991–2020 the last spring frost came before the first date, and in half the first fall frost came before the second (a date in January or February means the following winter). The growing season is NOAA's typical count of frost-free days, worked out year by year, so it can differ by a few days from the gap between the two dates (by more where frost is rare). Hot days, rain (with melted snow) and snowfall are 1991–2020 yearly averages. A town's station is the nearest NOAA station within 25 miles whose winter lows match the place's (within 5°F on the hardiness map's coldest-night figure), so a valley station is not used for a hilltop town. A low spot or a hillside on your own land can frost earlier or later.

Hardiness zone: the 2023 USDA map, which sorts places by the average coldest night of the year (1991–2020) into 10°F zones split into 5°F halves. It is read at the town's center (the Census Bureau's point for the place).

Sources: NOAA NCEI U.S. Climate Normals, 1991–2020 (Sullivans Island, station USC00388405, 5 ft; Charleston City, station USW00013782, 10 ft); USDA Plant Hardiness Zone Map, 2023 (USDA Agricultural Research Service and Oregon State University PRISM). Compiled October 30, 2026.

U.S. Census Bureau, Population Estimates Program, Vintage 2025 (May 2026); U.S. Census Bureau, American Community Survey 2020-2024 5-year (B19013) (Jan 2026); U.S. Census Bureau, Building Permits Survey (Sep 2026).

Shortage designations: HRSA Health Professional Shortage Areas (primary care, mental health, dental), HRSA data, as of October 2026. Hospitals: CMS Care Compare hospital list (hospitals that report an emergency department), July 2026, located by the U.S. Census Bureau geocoder or, where it found no match, the USGS National Structures Dataset hospital point (a few hospitals neither finds are placed from their street address, or by their ZIP code's center only where that cannot change the count or the names shown); distances from the Census Bureau's center point of the county or town (2026 Gazetteer).

A Health Professional Shortage Area (HPSA) is the federal government's finding that an area, or a group of people in it, has too few primary-care doctors, dentists or mental-health providers for its population. A geographic designation covers everyone in the area; a population designation (for example “Low Income Population HPSA”) covers only that group. Some designations cover only some census tracts or county subdivisions (the “areas” counted). The designation types and statuses are HRSA's own words; a designation HRSA has proposed for withdrawal stays on its list until it is withdrawn, and only designations with status “Designated” are in the summary sentence. A designation is about how many providers there are, not the quality of care. Hospitals counted are acute-care, critical-access and rural emergency hospitals that report an emergency department to Medicare, under the name filed with Medicare or the hospital's current name; one Medicare listing can cover more than one campus. Veterans', military, children's and psychiatric hospitals are not counted, and no ratings are shown.

The shortage designations are Charleston County's; the hospital count is measured from the Census center point of Sullivan's Island.