Union County

Every recorded tornado

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

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.

Mapped landslides

Mapped by USGS Conterminous (40).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. May 24, 2023Hail$5.0 million
   National Weather Service narrative

   Hail damage to cars and downed tree limbs reported via mping. Damage reported is an estimate.

2. Nov 7, 2024Blizzard, Union County$4.0 million
   National Weather Service narrative

   Whiteout conditions due to blowing snow along with snow drifts were observed across U.S. Highways 64/87, and U.S. Highway 56/412 beginning late Thursday morning. Wind gusts across western and central Union County from various mesonet stations and the Clayton Municipal Airpark ASOS peaked at around 40 mph during this time. Cars piled up behind a jack-knifed semi-truck between Clayton and Des Moines. The emergency manager estimated around 100 cars impacted and needing help getting turned around and off the road. The highway was closed and remained closed until all vehicles and drivers were cleared off after a couple of hours later. One stranded and injured motorist was rescued by a…

3. Apr 2, 2012High Wind, Union County$375,000
   National Weather Service narrative

   Estimated wind gusts of 70 mph were reported near Gladstone, while the Clayton ASOS reported wind gusts up to 59 mph. These strong winds took out an estimated 50 power poles across the area.

4. May 23, 2010Tornado$325,000
   National Weather Service narrative

   There was damage to agricultural equipment. A single wide mobile home that had tie down straps was completely destroyed and the undercarriage was carried approximately 40 yards. No injuries reported.

5. May 23, 2010Tornado$250,000
   National Weather Service narrative

   Debris on Highway 56 was seen at mile post 93. Power lines were down, barbed wire fences and hay bales were all over. In addition, a steel building from a feed lot was destroyed, a cow with a broken leg was observed on the road, and a semi truck was turned over on private property. The tornado crossed the New Mexico-Oklahoma state line approximately 8.7 miles southeast of Seneca and continued into neighboring Cimarron County, Oklahoma.

6. May 23, 2010Tornado$125,000
   National Weather Service narrative

   Two tornadoes were reported from the same parent supercell thunderstorm. This is the second tornado with shorter track farther north.

7. Dec 15, 2021High Wind, Union County$100,000
   National Weather Service narrative

   An ASOS station in Clayton measured a peak wind gust of 76 mph. With several hours of high winds recorded across Union County, numerous reports of damage were received. In Amistad, fifteen power poles were snapped while two others were downed in Grenville and another two in Mount Dora. As a result, power was out to much of the area. An RV traveling along U.S. Highway 64 was overturned near Grenville, but no information was provided on extent of injuries. Damages are a rough estimate.

8. Jun 11, 2023Hail$80,000
   National Weather Service narrative

   Large hail caused vehicle and roof damage near Sedan.

9. Feb 25, 2020High Wind, Union County$75,000
   National Weather Service narrative

   The Clayton airport reported peak wind gusts between 58 mph and 67 mph for a few hours. An observer at the Holiday Hotel reported a peak wind gust up to 72 mph. A 75-ft pine tree toppled onto the Hass Funeral Home resulting in minor damage to the property. A metal roof was partially torn off a golf cart building at the Clayton Golf Club. Fortunately, no injuries occurred with these high winds. Damage amounts are estimated for minor damage to the roof of the funeral home, damage at the golf course, total loss of one trampoline, and a bed liner that blew out of a pick up truck.

10. Aug 12, 2023Thunderstorm Wind$50,000
    National Weather Service narrative

    Severe winds destroyed a wall and blew part of the roof off of an old horse barn. It also blew two fiberglass windows out of a metal barn.

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

105°F2 times, most recently Jul 30, 1934

All-time low

−21°FJan 4, 1959

Warmest night

74°FJul 26, 1917

Coldest day

−1°F2 times, most recently Jan 11, 1963

Wettest day

6.20 inApr 30, 1914

Snowiest day

18.5 inDec 29, 2006

Hottest year

2012mean 57.9°F

Coldest year

1929mean 50.8°F

Wettest year

194137.62 in

Driest year

19365.54 in

Snowiest season

55.3 in1923-24

Station Clayton Municipal Air Pk (USW00023051), 4,969 ft elevation, 6.4 miles from the population centre. Daily records from 1896 to October 26, 2026; 99.8% 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 USW00023051.
• 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.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• 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.