Potter County
Population 2,377 (2025) 861 sq mi
Potter County has recorded 20 tornadoes since 1950, 54th most of 66 counties in South Dakota; the most recent was on July 26, 2011.
Hazard fingerprint Each spoke is this county’s percentile among U.S. counties where that hazard occurs. How it is computed
- Tornado damage paths since 195020
At a glance
The record for Potter County in eight numbers. Each links to its section below.
Tornadoes since 1950
20
54th of 66 in South Dakota
Fewer than the typical South Dakota county, which has had 29
DetailsStrongest tornado
F2
June 18, 1964, 24.6 mile path
Snowiest season
84.7in
Winter of 2010-11
Tornadoes
About one every 3.8 years since 1950, none rated F3/EF3 or stronger.
Strongest
June 18, 1964
F2, 24.6 mile path
200 yards wide.
Most recent
Tuesday, July 26, 2011
EF0, 0.1 mile path
15 years ago.
Every recorded tornado
| Jul 26, 2011 | EF0 | 0.1 | 0 | 0 |
| Jun 16, 2009 | EF0 | 0.5 | 0 | 0 |
| Jun 16, 2009 | EF0 | 0.2 | 0 | 0 |
| Jun 24, 2006 | F0 | 1.0 | 0 | 0 |
| Jun 11, 2003 | F0 | 0.1 | 0 | 0 |
| May 21, 1995 | F0 | 0.1 | 0 | 0 |
| Aug 3, 1981 | F1 | 0.1 | 0 | 0 |
| Aug 3, 1981 | F1 | 0.1 | 0 | 0 |
| Jun 19, 1979 | F1 | 0.1 | 0 | 0 |
| Jun 6, 1971 | F0 | 0.1 | 0 | 0 |
| Jul 18, 1970 | F2 | 0.1 | 0 | 0 |
| Jun 22, 1966 | F1 | 0.1 | 0 | 0 |
| Jun 22, 1966 | F1 | 0.1 | 0 | 0 |
| Jul 22, 1965 | F1 | 0.1 | 0 | 0 |
| May 8, 1965 | F0 | 0.1 | 0 | 0 |
| May 8, 1965 | F0 | 0.1 | 0 | 0 |
| Jun 18, 1964 | F2 | 24.6 | 2 | 0 |
| Apr 19, 1955 | F2 | 18.2 | 0 | 0 |
| Apr 19, 1955 | F2 | 2.3 | 0 | 0 |
| Apr 19, 1955 | F2 | 10.8 | 0 | 0 |
- Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Potter County: 0.
- Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.
Storm Prediction Center severe weather database, 1950 to 2025.
Hurricanes and tropical storms
No tropical storm or hurricane has tracked within 100 miles since records began in 1851.
Wildfire and smoke
No large wildfire has been mapped here since satellite mapping began in 1984.
Smoke overhead
Smokiest year
2021: 61 days
Heavy smoke on 39 days in 2021, the most of any year.
Last 10 years
31.9 days a year
Medium or heavy smoke, 2016 to 2025.
2025
27 days
Medium or heavy smoke. 38 so far in 2026.
- A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.
NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.
Floods and flood insurance
No federal flood insurance claims are recorded for this county.
Flood events since 1996
- Flood10
- Flash Flood9
OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.
Drought
In severe drought or worse for 147 of 1,581 months since 1895 (9%); the longest spell lasted 33 months.
147
Months in severe drought or worse since 1895
60
Months in extreme drought
9%
Share of all months, severe or worse
36
Drought reports to the Weather Service since 1996
Lowest reading
August 1934
−8.35, extreme drought
Longest severe spell
33 months
May 1936 to January 1939.
Latest month
September 2026
+1.37, slightly wet
Last severe month: July 2021.
- The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.
NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.
Earthquakes
2 earthquakes of magnitude 4 or more within 50 miles since 1900; the largest was magnitude 4.4 in 1983.
0
Magnitude 2.5+ inside the county since 1973
6
Magnitude 3+ within 50 miles since 1973
2
Magnitude 4+ within 50 miles since 1900
0
Magnitude 5+ within 50 miles since 1900
Largest within 50 miles
March 4, 1983
Magnitude 4.4
16 km N of Fort Thompson, South Dakota; 47.9 miles away, 3.1 miles deep.
Most recent, magnitude 3 or more
May 30, 2024
Magnitude 3.7
38 km NNW of Pierre, South Dakota; 16.3 miles away.
Every earthquake of magnitude 4 or more within 50 miles
| Mar 4, 1983 | 4.4 | 47.9 |
| Dec 31, 1961 | 4.2 | 47.4 |
- Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
- Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).
USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.
Severe weather and other events
562 events in the National Weather Service record, 480 of them since 1996.
78
Hail reports, 1 inch or larger
10
Hail, 2 inches or larger
126
Damaging gusts, 58 mph+
93
Winter weather events since 1996
11
Heat events since 1996
39
Cold events since 1996
Largest hail
August 28, 2011
3.00 inches
Strongest measured or estimated gust
June 21, 1956
100 mph
More event types since 1996
| Lightning | 1 | 0 |
| Dense fog and smoke | 1 | 0 |
Costliest events since 1996
- Apr 10, 2023Flood$150,000
National Weather Service narrative
The snowfall during the season in northeast and central South Dakota exceeded normal levels, with many locations ranking among the top 10 for the snowiest seasons. Additionally, the late spring conditions were unusually cold, resulting in a persistent and exceptionally deep snowpack until early April. The depth of the snowpack ranged from 15 to 30 plus inches, containing approximately 4 to 8 inches of snow water equivalent. However, the weather pattern shifted to abnormally warm conditions in the middle of April. Starting from April 9th, temperatures rapidly rose into the 40s and 50s in areas with deep snowpack, and occasionally reached the 60s and 70s thereafter. The rapid…
- Apr 1, 2019Flood$110,000
National Weather Service narrative
The continuation of snowmelt from a much above normal snowfall winter combined with a historic heavy snow/blizzard in mid-April resulted in widespread flooding across central and northeast South Dakota. Countless roads along with thousands of acres of cropland were flooded throughout April. Impacts include damaged roads, culverts, and bridges, and livestock, homes, and businesses were affected. Delayed planting resulted across all of the region as well. Cattle and calves were stressed by the cold and wet pattern, as the mud and cold caused some sickness with the livestock. Flooded roads made it difficult for many farmers or ranchers to get to their fields or livestock. There was a…
- Sep 2, 1999Flash Flood$14,000
National Weather Service narrative
Very heavy rains from thunderstorms repeatedly going over the same area resulted in extensive flash flooding in a 30 to 40 mile wide band from Fort Pierre in southeast Stanley County to Hecla in northeast Brown County. Rainfall amounts in this corridor ranged from 3 to 7 inches. As a result, the communities of Blunt in Hughes County and Onida in Sully county were severely flooded. Most of the homes and businesses were flooded throughout Blunt and Onida causing severe damage. Only a few homes in these communities were spared from receiving water in there basements. Most homes also experienced sewer backup. The sewer systems in both Onida and Blunt were flooded and shutdown. Many…
- Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.
NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.
Weather records
From Onida 4 Nw, 25.2 miles from the county’s population centre, with records from 1921.
- All-time high
- 116°FJul 15, 2006
- All-time low
- −40°FJan 1, 2018
- Warmest night
- 83°F2 times, most recently Jul 3, 1949
- Coldest day
- −18°F2 times, most recently Jan 14, 1972
- Wettest day
- 6.21 inAug 2, 1953
- Snowiest day
- 17.0 inApr 11, 2019
- Hottest year
- 2021mean 51.0°F
- Coldest year
- 1996mean 41.1°F
- Wettest year
- 200729.01 in
- Driest year
- 19769.88 in
- Snowiest season
- 84.7 in2010-11
Median first snow
November 10
Earliest: October 1, 1999
Median last snow
April 5
Latest: May 14, 1916
0 of 78 winters had no measurable snow.
Station Onida 4 Nw (USC00396292), 1,851 ft elevation, 25.2 miles from the population centre. Daily records from 1921 to October 17, 2026; 98.5% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.
NOAA NCEI Global Historical Climatology Network Daily.
Federal disaster declarations
16 since 1953. The most recent: Flooding, July 6, 2023.
| Jul 6, 2023 | Flood | DR-4718-SD |
| Feb 27, 2023 | Winter Storm | DR-4689-SD |
| Apr 5, 2020 | Biological | DR-4527-SD |
| Mar 13, 2020 | Biological | EM-3475-SD |
| Jun 7, 2019 | Flood | DR-4440-SD |
| May 13, 2011 | Flood | DR-1984-SD |
| Mar 10, 2010 | Severe Storm | DR-1887-SD |
| Sep 10, 2005 | Coastal Storm | EM-3234-SD |
| Jul 22, 2005 | Severe Storm | DR-1596-SD |
| Apr 7, 1997 | Flood | DR-1173-SD |
| Jan 10, 1997 | Severe Storm | DR-1156-SD |
| May 26, 1995 | Flood | DR-1052-SD |
| Mar 14, 1995 | Snowstorm | DR-1045-SD |
| Jun 21, 1994 | Severe Storm | DR-1031-SD |
| May 3, 1986 | Flood | DR-764-SD |
| Jun 17, 1976 | Drought | EM-3015-SD |
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.
How this compares
Where Potter County stands among 66 counties in South Dakota and 3,143 in the United States.
| Tornadoes since 1950 | 20 | 54 / 66 |
| Tornadoes rated F3/EF3 or stronger | 0 | — |
| Tropical cyclones within 50 mi | 0 | — |
| Hurricane-strength passes within 50 mi | 0 | — |
| Wildfire acres since 1984 | 0 | — |
| Flood insurance claims | 0 | — |
| Flood insurance paid | $0 | — |
| Disaster declarations | 16 | 47 / 66 |
| Flood events since 1996 | 19 | 55 / 66 |
| Hail and wind events since 1996 | 271 | 57 / 66 |
| Winter storm events since 1996 | 93 | 61 / 66 |
| Reported damage since 1996 | $274,000 | 58 / 66 |
| River crests at major flood stage | 0 | — |
| High tide flooding days a year, last 10 years | 0.0 | — |
| Months in severe drought since 1895 | 147 | 29 / 66 |
| Medium or heavy smoke days a year, last 10 years | 31.9 | 15 / 66 |
| Earthquakes M4+ within 50 mi since 1900 | 2 | 23 / 66 |
| Earthquakes M2.5+ in the county since 1973 | 0 | — |
Neighbouring counties
| Dewey County | 28 | 0 |
| Edmunds County | 31 | 0 |
| Faulk County | 22 | 0 |
| Hyde County | 15 | 0 |
| Sully County | 22 | 0 |
| Walworth County | 30 | 0 |
Sources and vintage
Every number on this page comes from these public records.
- Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
- Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
- Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
- Storm events NOAA NCEI Storm Events Database, through 2026.
- Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
- Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
- Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00396292.
- River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
- Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
- Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
- Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.
Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.