Union County, South Dakota

Union County, South Dakota has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 63% of US counties. It ranks 21st of 66 counties in South Dakota. The costliest hazards here are inland flooding, tornadoes and drought. FEMA estimates about $16 million a year in expected losses, or roughly $972 per resident. Since 1969 it has been included in 17 federal disaster or emergency declarations for natural events (15 major disasters). The most recent was in August 2024 (severe storms, straight-line winds and flooding). About 1 in 40 homes here carry federal flood insurance (199 policies). Since 1978, federal flood insurance has paid about $7.5 million on 443 claims here, including $4.3 million for floods in 2011.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is very low and community resilience is relatively moderate in FEMA's measures.

The National Weather Service has logged 494 storm reports in Union County since 1954, with 0 deaths and 4 injuries and about $82.6 million in reported damage. The strongest on record here was an F3 tornado on June 7, 1965.

Source: NOAA Storm Events Database, county-based reports through Jul 1, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 7,588 housing units.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.