Clay County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Clay 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.

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.

Claims by ZIP code

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 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.

More event types since 1996

Costliest events since 1996

1. Jun 21, 2024Flood$6.5 million
   National Weather Service narrative

   Rainfall amounts across Clay County from June 20-22 ranged from around a third of an inch across southern areas to 1 to 2 inches across northern areas. Farther north and upstream, 6 to 10 inches of rain fell across portions of southeast South Dakota, with locally higher amounts in excess of 12 inches. This rainfall resulted in record flooding along the Vermillion River and extensive overland flooding along the adjoining flood plain.||Two primary residences were impacted by flood waters across the northern portion of the county with each reporting more than three feet of water in their basements. One owner along the Vermillion River lost 100 percent of their land while countless…

2. Mar 13, 2019Flood$440,000
   National Weather Service narrative

   Multiple rural roads under water. Other flooding resulted in extensive damage to public infrastructure including numerous county and township roads, culverts, and some bridges.

3. Sep 22, 2010Hail$250,000
   National Weather Service narrative

   Large hail damaged numerous vehicles with dent and cracked and broken windshields. Twelve skylights at a local Wal-Mart store were broken. Some damage to roofs and siding was also sustained.

4. Jul 27, 1997Thunderstorm Wind$200,000
   National Weather Service narrative

   Thunderstorm winds caused widespread tree and power line damage, resulting in several power outages. The worst damage was in Vermillion including the University of South Dakota Campus.

5. Apr 1, 2001Flood, Clay$200,000
   National Weather Service narrative

   Flooding of the Vermillion River was caused by snowmelt, heavy rain, and ice jams. The ice jams significantly aggravated the flooding in Davis, where several houses were damaged and parkland was flooded. Residents of at least six homes in Davis were evacuated. The floodwaters also washed over almost a half mile of state highway 18 near Davis. Elsewhere along the river, farmland and other lowlands were flooded.

6. May 29, 2008Tornado$100,000
   National Weather Service narrative

   A tornado destroyed a barn, damaged or destroyed several outbuildings, scattered lumber across a field, and damaged trees and power lines.

7. Nov 28, 2005Blizzard, Clay$50,000
   National Weather Service narrative

   Snowfall varying from 4 to 15 inches combined with winds gusting over 50 mph to produce blizzard conditions. The heaviest snowfalls were mostly near and west of the James River, in the area where a severe ice storm immediately preceded the blizzard. Several reports of 6 to 8 foot drifts were received from this area. Visibilities were lowered frequently to zero and travel was made impossible in many areas. Roads, including Interstate Highways 90 and 29 were closed for extended periods of time. Most schools and businesses that were not already closed because of the ice storm were forced to close. The winds during the blizzard continued to bring down power lines and poles, most of…

8. Jun 16, 2014Flood$50,000
   National Weather Service narrative

   Persistent moderate to heavy rain caused flooding of fields and other lowlands, including several roads, homes, and businesses. This flooding lasted for almost two days, and was aggravated locally by additional storms during that time. Some roads were damaged or washed out.

9. Jun 3, 2000Thunderstorm Wind$50,000
   National Weather Service narrative

   Thunderstorm winds caused widespread tree damage and destroyed a picnic shelter. A few vehicles were damaged by tree debris.

10. Jun 4, 2000Thunderstorm Wind$50,000
    National Weather Service narrative

    Thunderstorm winds uprooted trees and caused other tree and power line damage.

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

114°FJul 17, 1936

All-time low

−38°FJan 12, 1912

Warmest night

86°FJul 31, 1955

Coldest day

−15°FDec 22, 1989

Wettest day

6.38 inAug 18, 1937

Snowiest day

15.0 inNov 28, 1983

Hottest year

1931mean 54.4°F

Coldest year

1917mean 45.8°F

Wettest year

201840.56 in

Driest year

192510.87 in

Snowiest season

69.8 in2000-01

Station Vermillion 2 Se (USC00398622), 1,137 ft elevation, 3.3 miles from the population centre. Daily records from 1893 to October 22, 2026; 98.1% 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 USC00398622.
• 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.