Yankton County, South Dakota

What hazards hit Yankton County most?

The most frequent records are hail reports: 256 since 1956. 48% of its hail reports since 1956 fell in May and June. The rank column places the county among South Dakota's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Yankton County had?

NOAA records 29 tornadoes in Yankton County from 1954 to 2014, the strongest rated F4, with 0 deaths and 1 injury recorded in the county. That is 12th of 66 South Dakota counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 29 tornadoes whose track touched Yankton County since 1950 (NOAA's county records number 29, the same count); along their whole tracks they killed 1 person, 0 of them in Yankton County.

Map of the strongest tornado tracks in South Dakota.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Yankton County?

The most recent record with damage, injuries or deaths is the August 21, 2023 excessive heat (1 death).

Daily afternoon and evening heat indices ranged from 100 to 115 degrees with a maximum heat index of 115 degrees at Automated Weather Observing System site KYKN at Yankton on August 21. A direct fatality occurred in Yankton on the third day of excessive heat when a child was left in a vehicle for an extended time. At the time of the incident, the heat index was 112 degrees with an air temperature of 100 degrees.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1138230)

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Yankton County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Drought in the 2020-26: 39 records against 12 in the decade before, 39 of them forecast-zone records. High wind and dust storms in the 2020-26: 28 records against 9 in the decade before, 28 of them forecast-zone records. Cells marked z rose mostly through zone records. The local National Weather Service office files these once per forecast zone, so a change in how it draws its zones or splits a storm into records moves this count as much as the weather does; read it beside the Yankton County days with a record above.

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

48% of its hail reports since 1956 fell in May and June. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Yankton County

FEMA's register lists 16 declarations that include Yankton County: 13 major disasters, 3 emergencies and 0 fire management assistance declarations. Most were for flood (6) and severe storm (6).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Yankton County had?

NOAA's Storm Events Database holds 89 flood or flash flood records for Yankton County from 1997 to 2024, on 69 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Yankton County ranks 1551st of 2,942 U.S. counties.

The National Flood Insurance Program has paid $1.5 million on 62 claims filed in Yankton County; the most in one year was 22 in 2011. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Yankton County

FEMA's National Risk Index rates Yankton County Relatively Low overall, with an expected annual loss of $19.4 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Yankton County

1. Yankton County 878
2. Hutchinson County 832
3. Bon Homme County 812
4. Turner County 787
5. Knox County, NE 776
6. Clay County 708
7. Cedar County, NE 608

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in South DakotaEvery South Dakota tornado since 1950 and the counties with the most per square mile
• Hail in South DakotaThe state's hail reports, by county, year and month
• The South Dakota recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Yankton CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Yankton County's FEMA declarations (CSV)16 rows: every declaration that named the county, for your own analysis