Brown County, South Dakota
County storm and disaster record · FIPS 46013 · population 38,265 · 1,713 sq mi
NOAA's Storm Events Database holds 1,437 records for Brown County, South Dakota from 1950 through June 30, 2026, on 809 days; the most frequent are hail reports (438 records). The deadliest single record is the September 24, 1986 thunderstorm wind: 2 deaths and 5 injuries. FEMA has issued 19 declarations naming the county since 1969, 17 of them for natural hazards; the latest for a natural hazard was “Flooding” on July 6, 2023.
The record, 1950 to 2026
Storm records filed for the county each year (2026 to June 30, 2026). Before 1996 NOAA recorded only tornadoes (from 1950), thunderstorm wind and hail (from 1955).
- recorded, no damage figure
- under $100,000
- $100,000 or more
- $1 million or more
- $10 million or more, or a death
- $100 million or more, or 10 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- 1955: wind and hail recorded from 1955
- 1996: all 48 event types from 1996
- Storm records
- 1,437on 809 days, 1950 to June 30, 2026
- Deaths recorded
- 1044 injuries
- Damage, 2025 dollars
- $80Mas filed (scale steps before 1993)
- Tornadoes
- 84strongest F4
- FEMA declarations
- 19latest 2023
Source: NOAA NCEI Storm Events Database, records through June 30, 2026 (file revision 20260918); damage converted to 2025 dollars with the BLS CPI-U. Search the record at NCEI. BLS consumer price index.
What hazards hit Brown County most?
The most frequent records are hail reports: 438 since 1959. 52% of its hail reports since 1959 fell in June and July. 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.
| Hazard | Records | Days | First, last | Killed | Injured | Damage | Rank in state |
|---|---|---|---|---|---|---|---|
| Hail | 438 | 205 | 1959-2026 | 0 | 0 | $116K | 38 of 66 |
| Severe thunderstorm wind | 421 | 221 | 1955-2026 | 2 | 5 | $11K | 18 of 66 |
| Floods | 192 | 152 | 1997-2025 | 0 | 0 | $61M | 14 of 66 |
| Winter storms | 128 | 128 | 1996-2026 | 2 | 10 | – | 53 of 66 |
| Tornadoes | 84 | 60 | 1955-2025 | 2 | 28 | $18M | 14 of 66 |
| High wind and dust storms | 61 | 59 | 1996-2026 | 0 | 0 | – | 63 of 66 |
| Extreme cold | 50 | 50 | 1996-2026 | 3 | 0 | – | 41 of 66 |
| Drought | 30 | 30 | 2002-2025 | 0 | 0 | – | 46 of 66 |
| Heat | 13 | 13 | 2006-2025 | 0 | 0 | – | 45 of 66 |
| Fog, smoke and funnel clouds | 11 | 9 | 2008-2025 | 1 | 1 | – | 11 of 66 |
| Wildfires | 8 | 8 | 1999-2025 | 0 | 0 | $35K | 2 of 66 |
| Lightning | 1 | 1 | 2014-2014 | 0 | 0 | $2K | 37 of 66 |
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 Brown County had?
NOAA records 84 tornadoes in Brown County from 1955 to 2025, the strongest rated F4, with 2 deaths and 28 injuries recorded in the county. That is 14th 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 86 tornadoes whose track touched Brown County since 1950 (NOAA's county records number 84: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 3 people, 2 of them in Brown County.
| Date | Tornado | Rating | Path | Killed |
|---|---|---|---|---|
| 1973-07-01 17:15, as SPC files it | Unnamed | F3 | 0.3 mi | 1 |
| 1961-06-21 14:30, as SPC files it | Castlewood | F3 | 156.3 mi | 1 |
| 1966-07-31 20:00, as SPC files it | Aberdeen | F2 | 2.3 mi | 1 |
| 2002-06-23 19:24, as SPC files it | Westport | F4 | 9 mi | 0 |
| 2002-06-23 18:53, as SPC files it | Westport | F3 | 10 mi | 0 |
| 1996-05-31 16:52, as SPC files it | Aberdeen | F3 | 32 mi | 0 |
| 1969-06-25 15:15, as SPC files it | Groton | F3 | 1.5 mi | 0 |
| 1965-05-20 16:45, as SPC files it | Unnamed | F3 | 3.8 mi | 0 |
Map of the strongest tornado tracks in South Dakota.
Every tornado record filed for Brown County (84)
| Date | Place | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2025-07-13 | Nahon, Brown County | EF0 0.1 mi x 10 yd | 0 | 0 | – |
| 2022-05-07 | Aberdeen, Brown County | EF0 0.01 mi x 10 yd | 0 | 0 | – |
| 2022-05-07 | Columbia, Brown County | EF0 0.01 mi x 10 yd | 0 | 0 | – |
| 2022-05-07 | Rudolph, Brown County | EF0 0.01 mi x 10 yd | 0 | 0 | – |
| 2020-06-07 | Frederick, Brown County | EF0 5.35 mi x 50 yd | 0 | 0 | – |
| 2017-06-13 | Groton, Brown County | EF0 0.1 mi x 10 yd | 0 | 0 | – |
| 2012-06-01 | Columbia, Brown County | EF0 0.48 mi x 10 yd | 0 | 0 | – |
| 2010-05-22 | Houghton, Brown County | EF2 1.29 mi x 100 yd | 0 | 0 | – |
| 2010-05-22 | Barnard, Brown County | EF0 1.6 mi x 50 yd | 0 | 0 | – |
| 2008-08-14 | Aberdeen, Brown County | EF0 0.15 mi x 10 yd | 0 | 0 | – |
| 2007-07-15 | Winship, Brown County | EF0 0.1 mi x 10 yd | 0 | 0 | – |
| 2005-06-26 | Westport, Brown County | F0 0.2 mi x 10 yd | 0 | 0 | – |
| 2005-06-07 | Hecla, Brown County | F1 0.1 mi x 30 yd | 0 | 0 | – |
| 2005-06-07 | Frederick, Brown County | F1 0.1 mi x 30 yd | 0 | 0 | – |
| 2005-06-07 | Groton, Brown County | F0 0.1 mi x 20 yd | 0 | 0 | – |
| 2005-05-08 | Frederick, Brown County | F0 0.1 mi x 25 yd | 0 | 0 | – |
| 2004-05-29 | Bath, Brown County | F0 0.3 mi x 30 yd | 0 | 0 | – |
| 2004-05-29 | Bath, Brown County | F0 0.1 mi x 10 yd | 0 | 0 | – |
| 2002-06-23 | Barnard, Brown County | F0 | 0 | 0 | – |
| 2002-06-23 | Barnard, Brown County | F4 9 mi x 900 yd | 0 | 0 | – |
| 2002-06-23 | Barnard, Brown County | F3 10 mi x 900 yd | 0 | 0 | – |
| 2002-06-23 | Barnard, Brown County | F0 0.3 mi x 50 yd | 0 | 0 | – |
| 2002-06-23 | Barnard, Brown County | F1 3 mi x 500 yd | 0 | 0 | – |
| 2000-07-11 | Aberdeen, Brown County | F0 0.1 mi x 10 yd | 0 | 0 | – |
| 1999-07-27 | Hecla, Brown County | F0 0.5 mi x 10 yd | 0 | 0 | – |
| 1998-06-26 | Groton, Brown County | F0 0.2 mi x 10 yd | 0 | 0 | – |
| 1996-07-17 | Groton, Brown County | F0 0.3 mi x 10 yd | 0 | 0 | – |
| 1996-05-31 | Putney, Brown County | F0 0.3 mi x 10 yd | 0 | 0 | – |
| 1996-05-31 | Aberdeen, Brown County | F1 1 mi x 50 yd | 0 | 0 | – |
| 1996-05-31 | Aberdeen, Brown County | F0 0.3 mi x 15 yd | 0 | 0 | – |
| 1996-05-31 | Aberdeen, Brown County | F0 0.3 mi x 10 yd | 0 | 0 | – |
| 1996-05-31 | Aberdeen, Brown County | F3 27 mi x 400 yd | 0 | 1 | $1.4M |
| 1996-05-31 | Aberdeen, Brown County | F0 0.5 mi x 15 yd | 0 | 0 | – |
| 1995-07-16 | Aberdeen, Brown County | F0 0.1 mi x 10 yd | 0 | 0 | – |
| 1994-07-18 | Aberdeen, Brown County | F0 0.1 mi x 10 yd | 0 | 0 | – |
| 1990-06-01 | Brown County | F0 0.3 mi x 20 yd | 0 | 0 | – |
| 1990-06-01 | Brown County | F0 3 mi x 30 yd | 0 | 0 | – |
| 1987-08-15 | Brown County | F1 2 mi x 50 yd | 0 | 0 | – |
| 1986-07-17 | Brown County | F0 0.1 mi x 23 yd | 0 | 0 | – |
| 1985-08-22 | Brown County | F0 0.2 mi x 10 yd | 0 | 0 | – |
| 1985-07-17 | Brown County | F0 0.2 mi x 3 yd | 0 | 0 | – |
| 1985-05-08 | Brown County | F0 0.1 mi x 3 yd | 0 | 0 | – |
| 1984-08-26 | Brown County | F0 0.1 mi x 3 yd | 0 | 0 | – |
| 1984-08-19 | Brown County | F1 0.1 mi x 3 yd | 0 | 0 | $25K step |
| 1984-07-02 | Brown County | F0 0.1 mi x 3 yd | 0 | 0 | – |
| 1982-06-11 | Brown County | F0 0.1 mi x 10 yd | 0 | 0 | $30 step |
| 1981-06-21 | Brown County | F0 | 0 | 0 | – |
| 1980-08-20 | Brown County | F0 0.1 mi x 33 yd | 0 | 0 | $25K step |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1980-05-29 | Brown County | F0 | 0 | 0 | – |
| 1979-06-19 | Brown County | F1 | 0 | 0 | $2.5M step |
| 1978-06-15 | Brown County | F2 | 0 | 15 | $250K step |
| 1977-07-10 | Brown County | 0 | 0 | – | |
| 1977-06-22 | Brown County | F0 0.6 mi x 13 yd | 0 | 0 | – |
| 1975-06-20 | Brown County | F1 2.5 mi x 20 yd | 0 | 0 | $25K step |
| 1975-06-20 | Brown County | F0 | 0 | 0 | – |
A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.
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 Brown County?
The most recent record with damage, injuries or deaths is the March 10, 2025 wildfire ($35,000 in damage in 2025 dollars).
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-29 | Thunderstorm WindStratford, Brown County | 56 kt wind | 0 | 0 | – |
| 2026-06-29 | HailGroton, Brown County | 1.00 in hail | 0 | 0 | – |
| 2026-06-29 | High WindBrown County · forecast zone Brown | 52 kt wind | 0 | 0 | – |
| 2026-06-29 | High WindBrown County · forecast zone Brown | 59 kt wind | 0 | 0 | – |
| 2026-06-29 | High WindBrown County · forecast zone Brown | 76 kt wind | 0 | 0 | – |
| 2026-06-28 | Thunderstorm WindGroton Municipal Airport, Brown County | 61 kt wind | 0 | 0 | – |
| 2026-06-27 | Thunderstorm WindAberdeen, Brown County | 65 kt wind | 0 | 0 | – |
| 2026-06-15 | Thunderstorm WindGroton, Brown County | 52 kt wind | 0 | 0 | – |
| 2026-06-09 | Thunderstorm WindAberdeen, Brown County | 61 kt wind | 0 | 0 | – |
| 2026-06-09 | Thunderstorm WindAberdeen, Brown County | 61 kt wind | 0 | 0 | – |
| 2026-06-09 | Thunderstorm WindAberdeen, Brown County | 61 kt wind | 0 | 0 | – |
| 2026-06-09 | Thunderstorm WindAberdeen, Brown County | 61 kt wind | 0 | 0 | – |
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
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 1986-09-24 | Thunderstorm WindBrown County | 2 | 5 | – | |
| 1973-07-01 | TornadoBrown County | F3 0.3 mi x 30 yd | 1 | 3 | $25K step |
| 1966-07-31 | TornadoBrown County | F2 2.3 mi x 253 yd | 1 | 3 | $250K step |
| 2019-09-15 | Dense FogBrown County · forecast zone Brown Dense fog contributed to a fatal two vehicle accident which occurred four miles west of Aberdeen around 8 am on Highway 12. A teenage boy was pulling onto Highway 12 in dense fog when his car was struck by a truck traveling east. The teenager died at the hospital from the injuries he sustained. The other vehicles' ... | 1 | 1 | – | |
| 2018-01-25 | Extreme Cold/Wind ChillBrown County · forecast zone Brown A 68 year-old Brown county woman died due to exposure to the cold. She was found near a grove of trees near Hecla on Thursday, January 25th. | 1 | 0 | – | |
| 2015-02-02 | Cold/Wind ChillBrown County · forecast zone Brown An 88-year old woman in Columbia died from exposure as she had fallen and could not get back up. Low temperatures were in the single digits below zero with wind chills as low as 20 to 25 below zero. | 1 | 0 | – | |
| 2013-04-10 | Winter StormBrown County · forecast zone Brown A large slow moving upper level low pressure area moving across the region brought several rounds of heavy snow to much of central and northeast South Dakota. Snowfall amounts from 6 to as much as 22 inches occurred over the several day period. Travel became difficult if not impossible with some roads closed for a ... | 1 | 0 | – | |
| 2011-03-08 | Cold/Wind ChillBrown County · forecast zone Brown A 97-year old Aberdeen woman died from exposure to the cold when she went outside her apartment patio and the door locked behind her. The woman was believed to be outside for 8 to 10 hours. The overnight low was 2 degrees above zero. The winds averaged around 10 mph through the night giving a wind chill of around 10 ... | 1 | 0 | – |
A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2019-06-01 | FloodWinship, Brown County | 0 | 0 | $42M | |
| 2005-07-01 | FloodBrown County · forecast zone Brown | 0 | 0 | $9.7M | |
| 2007-05-05 | Flash FloodWarner, Brown County | 0 | 0 | $7.1M | |
| 1996-05-31 | TornadoAberdeen, Brown County | F3 27 mi x 400 yd | 0 | 1 | $1.4M |
| 2019-04-01 | FloodWinship, Brown County | 0 | 0 | $860K | |
| 1998-05-11 | FloodBrown County · forecast zone Brown | 0 | 0 | $833K | |
| 2023-04-10 | FloodWinship, Brown County | 0 | 0 | $291K | |
| 2009-03-20 | FloodWestport, Brown County | 0 | 0 | $275K |
Before 1993 NOAA filed damage by category, not amount, so the list above starts in 1993. The highest category filed here before then (entered as $2.5M, in the dollars of the day) holds: June 19, 1979 (tornado, Brown County).
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 Brown 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).
| Hazard | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020-26 |
|---|---|---|---|---|---|---|---|---|
| Hail | 1 | 7 | 13 | 55 | 63 | 118 | 126 | 55 |
| Severe thunderstorm wind | 5 | 13 | 16 | 41 | 49 | 78 | 95 | 124 |
| Floods | – | – | – | – | 19 | 44 | 77 | 52 |
| Winter storms | – | – | – | – | 17 | 30 | 54 | 27 |
| Tornadoes | 6 | 7 | 17 | 17 | 13 | 15 | 4 | 5 |
| High wind and dust storms | – | – | – | – | 6 | 7 | 13 | 35 |
Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).
What time of year?
52% of its hail reports since 1959 fell in June and July. The two busiest months are in violet.
The values, month by month
Jan 47 · Feb 46 · Mar 55 · Apr 96 · May 140 · Jun 321 · Jul 319 · Aug 232 · Sep 69 · Oct 28 · Nov 33 · Dec 51 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
Federal disaster declarations for Brown County
FEMA's register lists 19 declarations that include Brown County: 16 major disasters, 3 emergencies and 0 fire management assistance declarations. Most were for flood (9) and severe storm (6).
| Declared | Number | Type | Title |
|---|---|---|---|
| 2023-07-06 | DR-4718 | Flood | Flooding |
| 2020-04-05 | DR-4527 | Biological | Covid-19 Pandemic |
| 2020-03-13 | EM-3475 | Biological | Covid-19 |
| 2019-06-07 | DR-4440 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| 2011-05-13 | DR-1984 | Flood | Flooding |
| 2010-05-13 | DR-1915 | Flood | Flooding |
| 2009-06-16 | DR-1844 | Severe Storm | Severe Storms and Flooding |
| 2007-05-22 | DR-1702 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| 2005-12-20 | DR-1620 | Severe Storm | Severe Winter Storm |
| 2005-09-10 | EM-3234 | Coastal Storm | Hurricane Katrina Evacuation |
| 2001-05-17 | DR-1375 | Flood | Severe Winter Storms, Flooding, and Ice Jams |
| 1998-06-01 | DR-1218 | Flood | Flooding, Severe Storms, Tornadoes |
| 1997-04-07 | DR-1173 | Flood | Severe Flooding, Sever Winter Storms,Heavy Rains High Winds |
| 1997-01-10 | DR-1156 | Severe Storm | Severe Winter Storms and Blizzard Conditions |
| 1995-05-26 | DR-1052 | Flood | Flooding |
| 1994-06-21 | DR-1031 | Severe Storm | Severe Storms and Flooding |
| 1993-07-19 | DR-999 | Severe Storm | Severe Storms, Tornadoes & Flooding |
| 1976-06-17 | EM-3015 | Drought | Drought |
| 1969-04-18 | DR-257 | Flood | Flooding |
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 Brown County had?
NOAA's Storm Events Database holds 192 flood or flash flood records for Brown County from 1997 to 2025, on 152 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Brown County ranks 519th of 2,942 U.S. counties.
The National Flood Insurance Program has paid $3.3 million on 484 claims filed in Brown County; the most in one year was 169 in 2007. Claims count insured losses only: uninsured flood damage is not in this file.
The values, year by year
1978: 104 · 1979: 31 · 1980: 5 · 1982: 3 · 1983: 21 · 1984: 4 · 1986: 9 · 1993: 2 · 1995: 4 · 1997: 81 · 1999: 1 · 2000: 1 · 2001: 1 · 2004: 1 · 2007: 169 · 2009: 11 · 2010: 14 · 2011: 17 · 2013: 1 · 2019: 2 · 2022: 2; the other years: 0.
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 Brown County
FEMA's National Risk Index rates Brown County Relatively Low overall, with an expected annual loss of $36.6 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.
| Hazard | Risk rating | Expected annual loss | Modeled frequency |
|---|---|---|---|
| Winter Weather | Very High | $1.5M | 20 a year (modeled) |
| Cold Wave | Relatively High | $16M | 13 a year (modeled) |
| Hail | Relatively Moderate | $1.5M | 3.9 a year (modeled) |
| Strong Wind | Relatively Moderate | $1.7M | 2.6 a year (modeled) |
| Ice Storm | Relatively Moderate | $534K | once in about 3 years (modeled) |
| Tornado | Relatively Moderate | $2.9M | about once a year (modeled) |
| Wildfire | Relatively Low | $353K | once in about 849 years (modeled) |
| Riverine Flooding | Relatively Low | $11M | 5.2 a year (modeled) |
Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.
Counties that share a border with Brown County
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 Brown CountyThe hazard risk calculator: 18 hazards beside the county's record
- Download Brown County's FEMA declarations (CSV)19 rows: every declaration that named the county, for your own analysis