South Dakota has recorded 16,536 hail events from 1955 to 2024, placing the state in the top 10 nationally (rank #6 of 50). The largest hailstone documented in South Dakota measured 8 inches — softball-sized. Since 1996, the National Weather Service has logged approximately $13.1M in property and crop damage from South Dakota hail, with the heaviest activity concentrated in June (4,898 events, the state’s busiest hail month) and the most active period (events per year) being 2000-09.
The interactive map below plots every recorded South Dakota hail report from the NOAA Storm Prediction Center archive. Use the Min Size buttons to focus on damaging hail (1.75″ golf-ball and larger), or filter by Era to see how activity has shifted over the decades.
Interactive South Dakota Hail Storm Map
South Dakota hail by the numbers
| Metric | South Dakota value |
|---|---|
| Total recorded hail events (1955-2024) | 16,536 |
| National rank (event volume) | #6 of 50 states |
| Largest hailstone on record | 8″ (softball-sized) |
| Busiest month | June (4,898 events) |
| Most active period (events/year) | 2000-09 |
| Total recorded damage (1996+) | $13.1M |
| Hail-related injuries (1996+) | 41 |
10 largest hailstones ever recorded in South Dakota
These are the top ten hail reports in South Dakota ranked by hailstone diameter. Sizes are NOAA’s measured-or-estimated diameter at time of report.
| Date | Hail size | Comparison | Reported damage | Casualties |
|---|---|---|---|---|
| 2010-07-23 | 8″ | softball-sized | — | 5 injured |
| 2007-08-21 | 6.88″ | softball-sized | — | — |
| 2007-08-21 | 6.13″ | softball-sized | — | — |
| 2015-06-19 | 6″ | softball-sized | — | — |
| 1968-06-22 | 6″ | softball-sized | — | — |
| 1990-07-07 | 5″ | softball-sized | — | 1 injured |
| 1991-05-28 | 5″ | softball-sized | — | 1 injured |
| 1992-06-16 | 5″ | softball-sized | — | — |
| 1955-06-28 | 5″ | softball-sized | — | — |
| 1957-07-02 | 5″ | softball-sized | — | — |
Costliest South Dakota hailstorms since 1996
Property loss totals come from the National Weather Service’s Storm Events Database. Pre-1996 figures are excluded because the dataset used categorical loss codes rather than dollar amounts before that year.
| Date | Hail size | Property + crop loss | Casualties |
|---|---|---|---|
| 2018-06-29 | 2″ | $2.0M | — |
| 2021-08-05 | 3.5″ | $500K + $175K crop | — |
Hail size distribution in South Dakota
How South Dakota’s 16,536 hail events break down by hailstone size. Hail under 1″ is treated as marginally severe; the National Weather Service issues severe-thunderstorm warnings starting at 1″ (quarter size).
| Hailstone size | Events | Share of South Dakota total |
|---|---|---|
| Under 1″ (pea to dime) | 5,351 | 32.4% |
| 1.00-1.74″ (quarter) | 6,872 | 41.6% |
| 1.75-1.99″ (golf ball) | 2,843 | 17.2% |
| 2.00-2.74″ (egg / hen-egg) | 792 | 4.8% |
| 2.75-3.99″ (baseball) | 572 | 3.5% |
| 4.00″+ (softball or larger) | 106 | 0.6% |
Activity by decade
Recorded hail events have risen across most US states over the decades — partly because of more severe weather, but largely because of vastly improved spotter networks, mobile reporting, and dual-polarisation radar coverage that came online widely after 2010. The events-per-year column normalises the 45-year pre-2000 bucket against the modern 10-year and 5-year periods so the trend is comparable.
| Period | Total events | Events per year |
|---|---|---|
| Pre-2000 (1955-99) | 3,307 | 73 |
| 2000-09 | 6,232 | 623 |
| 2010-19 | 4,866 | 487 |
| 2020-24 | 2,131 | 426 |
When South Dakota’s hail season peaks
South Dakota’s hail activity by calendar month, summed across all years from 1955 to 2024.
| Month | Events |
|---|---|
| January | 0 |
| February | 5 |
| March | 76 |
| April | 489 |
| May | 2,273 |
| June | 4,898 |
| July | 4,648 |
| August | 3,221 |
| September | 786 |
| October | 124 |
| November | 15 |
| December | 1 |
Where South Dakota fits in the US hail picture
South Dakota sits firmly inside what meteorologists call Hail Alley — the high-frequency hail corridor running from northern Texas through Oklahoma, Kansas, Nebraska and the eastern Plains. The ingredients are the same wherever the alley runs: warm moist air pulled up from the Gulf of Mexico colliding with cold dry air spilling east off the Rockies, capped by a strong mid-level jet. That setup builds the deep, rotating supercells that loft hailstones high enough to grow to baseball- and softball-size before they fall.
Compare South Dakota’s hail risk with its neighbours: North Dakota hail, Minnesota hail, Iowa hail, Nebraska hail, Wyoming hail, Montana hail.
Frequently asked questions about South Dakota hailstorms
What is the largest hailstone ever recorded in South Dakota?
According to NOAA Storm Prediction Center data, the largest measured hailstone in South Dakota was 8 inches in diameter — softball-sized. The map above plots that event along with every other hail report on file for the state.
When does South Dakota get the most hail?
June is South Dakota’s busiest hail month, with 4,898 recorded events — the highest single-month total in the state’s NOAA record. Most South Dakota hail falls in the spring and early-summer convective season; you can see the full month-by-month breakdown in the seasonality table above.
Where in South Dakota does hail occur most often?
Use the interactive map above to identify the highest-density hail corridors. Pan, zoom and click any point to see the date, size and reported damage for that event. Patterns vary across South Dakota — in many states the heaviest activity clusters along specific corridors driven by local terrain, lake effects, or jet-stream positioning.
Is South Dakota’s hail activity getting worse?
Roughly steady or modestly declining in the recent record — but interpret the trend with care. The recorded count has risen across nearly every state because spotter networks, mobile reporting apps, and dual-polarisation radar all expanded dramatically after about 2010. So a rising count partly reflects better detection rather than purely worse weather. The size-distribution and damage tables above are slightly less affected by this reporting bias.
How is hail size measured?
Reports use estimated maximum hailstone diameter in inches, usually compared to common objects: 0.75″ (penny), 1″ (quarter, the severe threshold), 1.75″ (golf ball), 2″ (egg), 2.75″ (baseball), 4″ (softball). The largest verified US hailstone, recorded in Vivian, South Dakota in 2010, measured 8 inches across.
Data sources and limitations
All hail event data on this page comes from the NOAA Storm Prediction Center SVRGIS dataset, accessed via an Esri feature service. The dataset contains over 400,000 individual US hail reports from 1955 to 2024. Property and crop loss values are recorded in actual dollar amounts from 1996 onward (categorical codes were used pre-1996, so loss totals on this page exclude those earlier years). Hailstone sizes are reported as measured-or-estimated maximum diameters; report density is influenced by population, road networks, and the modernisation of spotter networks over time.
Related Mapscaping resources: US Hailstorms map (national hub) · NOAA Storm Reports map (tornadoes, hail and wind)
