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 storm within 100 miles

1. Tropical storms and hurricanes (34 kt or more, still tropical) at closest approach. Post-tropical remnants with gale-force winds are listed but not counted. Direct: track within 50 miles; near: within 100 miles. Distance is measured to the county boundary for counties and to the city centre for cities, using positions interpolated hourly between HURDAT2 fixes.

National Hurricane Center HURDAT2, 1851 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.

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 NASA (1).

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. Sep 14, 2008High Wind, Union$5.5 million
   National Weather Service narrative

   Strong winds of 40 to 50 miles per hour were sustained for several hours. Gusts over 60 mph were common. Widespread damage occurred across the region, from trees being blown down on powerlines, to significant crop losses and structural damage.

2. Jun 1, 1997Flash Flood$3.0 million
   National Weather Service narrative

   Thunderstorms moved repeatedly over the same areas causing most creeks and streams to overflow their banks and flood county roads. Several residents were evacuated as up to 7.5 inches of rain fell in less than 24 hours.

3. Nov 10, 2002Tornado$500,000
   National Weather Service narrative

   The tornado moved into the northwest part of the county from Logan County, tracking northeast across rural areas. Nine homes were damaged, four of which were completely destroyed. Half a dozen barn and sheds were destroyed. A 400-foot metal hi-tension cellular tower was toppled and destroyed and numerous cars were totalled. The worst damage occurred to a modular home along Newton-Perkins Road. Two individuals in the home were severely injured.

4. Mar 14, 2024Tornado$500,000
   National Weather Service narrative

   The tornado developed in far western Union County near Newton Perkins Road and strengthened as it moved east across Lunda and Morse Roads where it caused some roof damage to homes. The tornado quickly strengthened further and affected a number of homes along Evans Road as it crossed State Route 739 and then continued southeast to areas just north of Broadway. Across portions of that corridor, damage was consistent with wind speeds of 115 to 125 mph. One modular home was completely destroyed with its contents thrown downstream nearly a half mile and another home lost a majority of its roof with exterior wall collapse. ||Significant tree damage was observed near Broadway, including…

5. Jun 13, 2022Thunderstorm Wind$250,000
   National Weather Service narrative

   Numerous trees and power lines were downed throughout Union County, including in the Marysville area.

6. Oct 25, 2000Dense Fog, Union$100,000
   National Weather Service narrative

   A tanker truck hauling 8,600 gallons of gasoline crashed into a car and three other commercial vehicles and exploded. Two people were killed and one injured. The accident occurred in fog that reduced visibility to near zero.

7. Mar 9, 2002High Wind, Union$75,000
   National Weather Service narrative

   A widespread area of high winds blew down trees, power poles, and various other smaller structures and signs. At one time, approximately 100,000 people were without power. One man was killed when his semi tractor overturned, and several others were injured in automobile accidents, and when trees fell on the buildings that they were in. Two people were briefly trapped in a mobile home when a tree fell on it. The hardest hit area was just southwest of Columbus in Grove City where an 84 mph wind was recorded and several structures at the high school were damaged or destroyed.

8. Jun 6, 2010Tornado$64,000
   National Weather Service narrative

   Damage from the tornado consisted of several large tree limbs and trees down. Light structural damage occurred to several homes near State Route 38 and Timberview Drive. This damage included the loss of shingles and siding. The most significant damage occurred to a home along State Route 38 which suffered near total roof loss. Based on the damage, wind speeds were estimated to be around 85 miles per hour.

9. Nov 10, 2002Tornado$50,000
   National Weather Service narrative

   A tornado briefly touched down near the intersection of Boundary and McPeek Roads, causing damage to a barn and the roof of a nearby home.

10. Jun 29, 1998Flash Flood$50,000

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

109°FJul 14, 1936

All-time low

−23°FJan 10, 1982

Warmest night

79°F3 times, most recently Jul 20, 1980

Coldest day

−9°FJan 20, 1985

Wettest day

4.82 inJun 2, 1997

Snowiest day

16.0 inDec 23, 2004

Hottest year

1998mean 54.9°F

Coldest year

1917mean 47.4°F

Wettest year

201155.43 in

Driest year

199124.08 in

Snowiest season

50.8 in1935-36

Station Marysville (USC00334979), 970 ft elevation, 4.9 miles from the population centre. Daily records from 1917 to October 27, 2026; 98.3% 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 USC00334979.
• 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.