States › South Dakota › Brown County
Brown County, South Dakota
Recorded hazard history: storm events since 1950, federal disaster declarations since 1953, flood insurance claims since 1978, and FEMA's risk index.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. NCEI storm records through 30 Jun 2026; OpenFEMA declarations refreshed 1 Oct 2026; NFIP claims as of 8 Sep 2026.
The NCEI record lists 1,437 events for Brown County, South Dakota, between 1950 and 2026; damaging wind account for the largest share.
That is 83.9 events per 100 square miles, in line with the South Dakota figure of 73.7, and 377.2 per 10,000 residents against 624.1 statewide.
63 events fall in the 12 months to 30 Jun 2026. NCEI attributes 10 deaths and 44 injuries to events in the county, with property damage estimated at $11M and crop damage at $43M.
FEMA has designated the county in 19 federal disaster declarations since 1953; the most recent is Flooding (major disaster, 6 Jul 2023).
National Flood Insurance Program policyholders in the county filed 484 claims since 1978, of which 387 were paid, totalling $3.3M (about $9K per paid claim). FEMA counts 114 residential flood policies in force.
FEMA's National Risk Index rates the county's overall risk as "Relatively Low" and its expected annual loss as "Relatively Low" ($37M a year across 18 hazards).
Compared with South Dakota and the United States
| Measure | Brown County | South Dakota | US |
|---|---|---|---|
| Recorded events since 1950 | 1,437 | 55,877 | 1,977,440 |
| Events per 100 square miles | 83.9 | 73.7 | 56.0 |
| Events per 10,000 residents | 377.2 | 624.1 | 59.6 |
| Events in the last 12 months | 63 | 2,303 | 62,008 |
| Deaths recorded by NCEI | 10 | 147 | 26,435 |
| Property damage (NCEI estimates) | $11M | $1.1B | $575B |
| NFIP claims per 1,000 residents | 12.7 | 4.5 | 8.1 |
| Average paid NFIP claim | $9K | $21K | $43K |
| Claims per 100 policies in force, last 10 years | 3.5 | 30.7 | 16.1 |
County-recorded events plus zone-recorded events whose forecast zone is named for the county. State and US rows include events recorded only by forecast zone. Rates use 2021 Census population and land area.
Events by decade
Trend: 874 events in the 20 years to 2025 against 387 in the 20 years before. Reporting practice changed in 1996 and again with automated reports in the 2000s, so decade totals measure the record as much as the weather.
Events by type
Hazard pages exist for hail, tornado, flood, wind and winter where the county has at least 10 recorded events. "Other" covers heavy rain, debris flow, dust, funnel clouds and similar reports.
Largest recorded events
| Date | Event type | Group | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|---|
| 24 Sep 1986 | Thunderstorm Wind | Wind | 0 mph | — | — | 2 | 5 | County |
| 31 Jul 1966 | Tornado | Tornado | F2 | $250K | — | 1 | 3 | County |
| 1 Jul 1973 | Tornado | Tornado | F3 | $25K | — | 1 | 3 | County |
| 15 Sep 2019 | Dense Fog | Fog | — | — | — | 1 | 1 | Forecast zone |
| 16 Dec 1996 | Blizzard | Winter | — | — | — | 1 | — | Forecast zone |
| 8 Mar 2011 | Cold/Wind Chill | Cold | — | — | — | 1 | — | Forecast zone |
| 10 Apr 2013 | Winter Storm | Winter | — | — | — | 1 | — | Forecast zone |
| 2 Feb 2015 | Cold/Wind Chill | Cold | — | — | — | 1 | — | Forecast zone |
| 25 Jan 2018 | Extreme Cold/Wind Chill | Cold | — | — | — | 1 | — | Forecast zone |
| 15 Jun 1978 | Tornado | Tornado | F2 | $250K | — | — | 15 | County |
| 25 Jun 1969 | Tornado | Tornado | F3 | $250K | — | — | 6 | County |
| 1 Jun 2019 | Flood | Flood | — | — | $36M | — | — | County |
| 3 Jan 1997 | Winter Storm | Winter | — | — | — | — | 3 | Forecast zone |
| 9 Jan 1997 | Blizzard | Winter | — | — | — | — | 3 | Forecast zone |
| 18 Feb 2013 | Blizzard | Winter | — | — | — | — | 3 | Forecast zone |
| 31 May 1996 | Tornado | Tornado | F3 | $750K | — | — | 1 | County |
| 16 Nov 1996 | Winter Storm | Winter | — | — | — | — | 1 | Forecast zone |
| 1 Jul 2005 | Flood | Flood | — | $88K | $6.3M | — | — | Forecast zone |
| 5 May 2007 | Flash Flood | Flood | — | $5.0M | — | — | — | County |
| 19 Jun 1979 | Tornado | Tornado | F1 | $2.5M | — | — | — | County |
Ranked by deaths, then injuries, then NCEI's damage estimate. Deaths and injuries are NCEI counts (direct plus indirect); no personal details are recorded here.
Federal disaster declarations
| Declared | Number | Type | Incident | Title | Programs |
|---|---|---|---|---|---|
| 6 Jul 2023 | DR-4718 | Major disaster | Flood | Flooding | Public assistance |
| 5 Apr 2020 | DR-4527 | Major disaster | Biological | Covid-19 Pandemic | Individual assistance, Public assistance |
| 13 Mar 2020 | EM-3475 | Emergency | Biological | Covid-19 | Public assistance |
| 7 Jun 2019 | DR-4440 | Major disaster | Flood | Severe Winter Storm, Snowstorm, And Flooding | Public assistance |
| 13 May 2011 | DR-1984 | Major disaster | Flood | Flooding | Public assistance |
| 13 May 2010 | DR-1915 | Major disaster | Flood | Flooding | Public assistance |
| 16 Jun 2009 | DR-1844 | Major disaster | Severe Storm | Severe Storms And Flooding | Public assistance |
| 22 May 2007 | DR-1702 | Major disaster | Severe Storm | Severe Storms, Tornadoes, And Flooding | Individual assistance, Public assistance |
| 20 Dec 2005 | DR-1620 | Major disaster | Severe Storm | Severe Winter Storm | Public assistance |
| 10 Sep 2005 | EM-3234 | Emergency | Coastal Storm | Hurricane Katrina Evacuation | Public assistance |
| 17 May 2001 | DR-1375 | Major disaster | Flood | Severe Winter Storms, Flooding, And Ice Jams | Public assistance |
| 1 Jun 1998 | DR-1218 | Major disaster | Flood | Flooding, Severe Storms, Tornadoes | Individual assistance, Public assistance |
| 7 Apr 1997 | DR-1173 | Major disaster | Flood | Severe Flooding, Sever Winter Storms,Heavy Rains High Winds | Individual assistance, Public assistance |
| 10 Jan 1997 | DR-1156 | Major disaster | Severe Storm | Severe Winter Storms And Blizzard Conditions | Public assistance |
| 26 May 1995 | DR-1052 | Major disaster | Flood | Flooding | Individual assistance, Public assistance |
| 21 Jun 1994 | DR-1031 | Major disaster | Severe Storm | Severe Storms And Flooding | Public assistance |
| 19 Jul 1993 | DR-999 | Major disaster | Severe Storm | Severe Storms, Tornadoes & Flooding | Individual assistance, Public assistance |
| 17 Jun 1976 | EM-3015 | Emergency | Drought | Drought | Public assistance |
| 18 Apr 1969 | DR-257 | Major disaster | Flood | Flooding | Individual assistance, Public assistance |
Declarations in which FEMA designated this county, from the OpenFEMA Disaster Declarations Summaries (v2). DR: major disaster; EM: emergency; FM: fire management assistance. Programs show whether individual or public assistance was made available.
Flood insurance claims
| Year of loss | Claims | Paid claims | Amount paid | Average paid |
|---|---|---|---|---|
| 2022 | 2 | 1 | $2,210 | $2,210 |
| 2019 | 2 | 1 | $404 | $404 |
| 2013 | 1 | 1 | $763 | $763 |
| 2011 | 17 | 14 | $265,545 | $18,967 |
| 2010 | 14 | 11 | $178,173 | $16,198 |
| 2009 | 11 | 8 | $106,633 | $13,329 |
| 2007 | 169 | 143 | $1,943,510 | $13,591 |
| 2004 | 1 | 1 | $2,396 | $2,396 |
| 2001 | 1 | 1 | $2,961 | $2,961 |
| 2000 | 1 | 0 | $0 | — |
| 1999 | 1 | 1 | $11,351 | $11,351 |
| 1997 | 81 | 52 | $441,214 | $8,485 |
| 1995 | 4 | 1 | $3,750 | $3,750 |
| 1993 | 2 | 0 | $0 | — |
| 1986 | 9 | 2 | $2,486 | $1,243 |
| 1984 | 4 | 1 | $358 | $358 |
| 1983 | 21 | 19 | $40,012 | $2,106 |
| 1982 | 3 | 1 | $502 | $502 |
| 1980 | 5 | 4 | $1,435 | $359 |
| 1979 | 31 | 28 | $24,485 | $874 |
| 1978 | 104 | 97 | $261,196 | $2,693 |
OpenFEMA NFIP claims (v3, as of 8 Sep 2026), aggregated by year of loss; amounts are building, contents and increased-cost-of-compliance payments as recorded. Repetitive-loss counts from the NFIP Multiple Loss Properties file (2 Aug 2026); policies in force from the NFIP Residential Penetration Rates file (3 Aug 2026).
National Risk Index
| Hazard (NRI) | Risk rating | Expected annual loss |
|---|---|---|
| Cold wave | $16,354,723 | |
| Inland flooding | $11,281,939 | |
| Tornado | $2,877,156 | |
| Strong wind | $1,653,158 | |
| Winter weather | $1,533,158 | |
| Hail | $1,508,772 | |
| Ice storm | $533,757 | |
| Heat wave | $402,169 | |
| Wildfire | $352,807 | |
| Earthquake | $67,642 | |
| Drought | $30,913 | |
| Lightning | $27,078 | |
| Landslide | $1,029 |
FEMA National Risk Index, December 2025 release. Ratings are FEMA's relative comparison of counties; expected annual loss is FEMA's modelled estimate of average yearly building, population and agriculture loss. See how to read the NRI.
Hurricane and tropical storm passes
No HURDAT2 track at tropical-storm strength passes within 100 miles of the county's centre point (through the 2025 season).
ZIP codes with flood claims
ZIP codes whose NFIP claims carry this county's code, with the number of claims. Five or more claims are needed for a ZIP page to be indexed.
Questions and answers
How often does it hail in Brown County, SD?
NCEI records 438 hail events in Brown County since 1950, in 60 different years; that is about 5.7 recorded events a year. 123 reports were golf-ball size (1.75 in) or larger.
Has Brown County had a tornado?
Yes. NCEI records 84 tornadoes in Brown County since 1950, 12 of them rated (E)F2 or stronger. Tornado deaths recorded: 2.
When was the last federal disaster declaration for Brown County?
6 Jul 2023: Flooding, a major disaster declaration for flood. The county appears in 19 declarations since 1953.
How many flood insurance claims have been filed in Brown County, and how much was paid?
484 NFIP claims since 1978, 387 of them paid, for $3.3M in total. FEMA publishes these figures redacted and aggregated; individual properties are not identified.
Is Brown County in the National Risk Index's high-risk band?
FEMA's National Risk Index (December 2025) rates the county "Relatively Low" for overall risk, "Relatively Low" for expected annual loss, "Relatively Low" for social vulnerability and "Very High" for community resilience. These ratings are FEMA's relative comparison across all US counties.
How does Brown County compare with the rest of South Dakota?
83.9 recorded events per 100 square miles against 73.7 statewide, and 12.7 NFIP claims per 1,000 residents against 4.5. The comparison table on this page shows each measure beside the state and national figures.
Provenance
Storm events: NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026 (public domain). Declarations: OpenFEMA DisasterDeclarationsSummaries v2, refreshed 1 Oct 2026. Flood claims: OpenFEMA NfipClaims v3 as of 8 Sep 2026; NfipMultipleLossProperties v1 (2 Aug 2026); NfipResidentialPenetrationRates v1 (3 Aug 2026). Risk index: FEMA National Risk Index, December 2025. Hurricane tracks: NHC HURDAT2 through 2025. Population and area: US Census Bureau, 2021 vintage. Built 1 Oct 2026; see the methodology and corrections pages. Hazard hubs: Hail · Tornado · Flood · Wind · Winter.