Mellette County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Mellette County: 0.
2. 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.

Every large fire

1. Large fires mapped by the Monitoring Trends in Burn Severity program since 1984: 1,000 acres or more in the West, 500 or more in the East. Prescribed burns are excluded. Acres here are the part of each perimeter inside this place.

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service), 1984 to 2026.

Smoke overhead

1. 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.

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. 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.

Every earthquake of magnitude 4 or more within 50 miles

1. 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).
2. 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.

Costliest events since 1996

1. Mar 30, 2009Blizzard, Mellette$300,000
   National Weather Service narrative

   The second blizzard in a week brought heavy snow and strong winds to the western South Dakota plains. Northwest wind gusts to 50 mph produced significant blowing and drifting snow, reducing visibilities to near zero for many hours. Reports of six to 12 inches of snow were common, with higher amounts across northwestern South Dakota. Interstate 90 and many other highways were closed for a considerable period of time. More livestock losses occurred during the peak of calving and lambing season.

2. Aug 20, 2000Thunderstorm Wind$200,000
   National Weather Service narrative

   High winds of unknown strength destroyed a new hog barn, moved two more off thier foundations and tore siding off another barn. The building that was destroyed was vacant, and no hogs were injured or killed.

3. Jun 5, 2008Flood$100,000
   National Weather Service narrative

   Flooding was observed along the White River, Little White River, Cottonwood Creek, and their tributaries across northern Mellette County.

4. Nov 6, 2008Blizzard, Mellette$100,000
   National Weather Service narrative

   An intense fall storm produced blizzard conditions across the South Dakota plains for over 24 hours. Precipitation started as rain during the day and changed to heavy, wet snow during the evening of the 5th. Snow and blowing snow continued through much of the 6th with visibility near zero much of the time. Snowfall amounts were six to 18 inches with drifts 12 feet high. More than two thousand power poles were downed, causing widespread power outages that affected thousands of residents. Some locations did not have power for over a week, especially across the Pine Ridge Reservation. Most roads across the area, including Interstate 90, were closed for 24 hours or longer. Many…

5. Mar 23, 2009Blizzard, Mellette$100,000
   National Weather Service narrative

   A powerful spring storm brought rain, snow, and very strong winds to western South Dakota. Precipitation started as rain, then changed to snow, and blizzard conditions developed. The heaviest snow fell over the northern Black Hills, where 18 to 48 inches of snow was measured. Ten to 20 inches of snow fell across far northwestern South Dakota, with drifts as high as ten feet. Most other locations received at least six inches of snow. Sustained winds of 30 to 55 mph, with gusts over 80 mph, were reported. Interstate 90 and other highways were closed for more than 24 hours. Some power outages were reported, mainly across the northern Black Hills and northwestern South Dakota. Tens of…

6. Jul 9, 2007Thunderstorm Wind$75,000
   National Weather Service narrative

   Roofs were torn off two houses and a trailer house was rolled three times. No injuries were reported.

7. Jul 22, 2012Thunderstorm Wind$60,000
   National Weather Service narrative

   Strong winds destroyed two trailer houses, damaged the school roof, and knocked down several power poles. A woman in one of the mobile homes was severely injured.

8. Jul 30, 2013Hail$50,000
   National Weather Service narrative

   A long-lived supercell thunderstorm developed over western Haakon County and moved south-southeast across south central South Dakota. Very large hail was reported in some areas, along with strong wind gusts, and a small tornado near Philip. The wind-driven hail caused extensive damage to houses from Corn Creek to Parmelee.

9. Aug 17, 2011Hail$40,000
   National Weather Service narrative

   Large hail caused significant damage to the roof and windows of a house and vehicles.

10. Jul 13, 2009Hail$40,000
    National Weather Service narrative

    Deputies and spotters reported quarter to baseball sized hail from Corn Creek at the junction of Highways 44 and 63 to Cedar Butte, which damaged automobiles.

1. 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.

All-time high

116°FJul 25, 1936

All-time low

−36°F2 times, most recently Feb 6, 1936

Warmest night

90°F2 times, most recently Aug 9, 1944

Coldest day

−18°FDec 22, 1989

Wettest day

4.59 inAug 2, 1922

Snowiest day

18.0 inNov 1, 1920

Hottest year

1934mean 53.6°F

Coldest year

1996mean 44.0°F

Wettest year

191533.49 in

Driest year

19348.92 in

Snowiest season

91.1 in2022-23

Station Wood (USC00399442), 2,180 ft elevation, 16.8 miles from the population centre. Daily records from 1913 to October 10, 2026; 99.0% 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.

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.

Neighbouring counties

• 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 USC00399442.
• 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.