Knox County

Every recorded tornado

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

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. Mar 7, 2008Winter Storm, Knox$750 million
   National Weather Service narrative

   Snow developed during the morning hours of the 7th, and continued for the next day and a half. Intensity varied through the day on the 7th, but during the evening hours the snow became rather light for a period of time. However, the snow intensified through the overnight and into the morning hours of the 8th. By the end of the event, between 9.0 and 15.0 inches of snow fell across the area. Gusty winds between 20 and 30 mph during the morning and afternoon of the 8th caused considerable blowing and drifting of snow. Many accidents were reported from this storm.

2. Jan 5, 2005Ice Storm, Knox$6.8 million
   National Weather Service narrative

   For the second time in just over two weeks, a devastating and historic winter storm affected Northern Ohio. Significant ice accumulations occurred over most of the area downing thousands of trees, causing widespread power outages and making travel nearly impossible. Low pressure over Missouri moved rapidly northeast on January 5th. This low moved across eastern Ohio early on January 6th and was responsible for producing a prolonged period of freezing rain. A mixture of rain and snow changed to freezing rain from west to east during the early morning hours of the 5th. Periods of freezing rain then continued for the remainder of the 5th and through the early morning hours of the…

3. Dec 22, 2004Winter Storm, Knox$5.4 million
   National Weather Service narrative

   A record setting winter storm affected northern Ohio on December 22nd and 23rd and dumped both heavy snow and freezing rain on Knox, Holmes, Wayne and Stark Counties. The impact and damage caused by this storm has been compared to the Blizzard of January 1978. Low pressure developed over eastern Texas early on the 22nd and then moved quickly northeast. The low eventually tracked across eastern Ohio during the morning hours of the 23rd after dumping nearly two feet of snow on portions of Ohio. The snow began around daybreak on the 22nd and then intensified during the afternoon. During the evening, warmer air spread into the area as the low approached from the southwest. This caused…

4. Sep 14, 2008High Wind, Knox$4.0 million
   National Weather Service narrative

   High winds associated with the remnants of Hurricane Ike began late in the afternoon of September 14th and then continued through much of the evening. Wind gusts were estimated to be as much as 70 mph. Damage in the county was extensive with thousands of trees and many utility poles downed. Widespread power outages occurred as well with some customers without power for as much as ten days. Home and building damage across the county was also extensive. The damage ranged from a few shingles torn off to significant structural damage caused by fallen trees landing on roofs. Awnings and gutters were torn off of some homes. Numerous vehicles were damaged by fallen trees and limbs and…

5. Jul 10, 2006Flash Flood$3.5 million
   National Weather Service narrative

   Heavy thunderstorm rains fell on the northeastern corner of Knox County during the afternoon and early evening hours of July 10th. A spotter near the intersection of State Route 3 and College Hill Road (just south of the Ashland County line) measured a storm total of 7.5 inches. Up to 7 inches of rain was reported in the Danville area with 5.5 inches of this total falling between 3 and 5 p.m. Both the Mohican River and Jelloway Creek quickly went into flood and caused considerable damage. Runoff from the heavy rains caused the Mohican River to rise more than a foot per hour through the evening hours. Campgrounds along Wally Road were especially hard hit by flooding from the…

6. Jun 27, 1998Flash Flood$3.0 million
   National Weather Service narrative

   Continuing heavy thunderstorm rains brought major flooding, which continued in many areas through the day. Approximately one hundred people were evacuated from their homes. A number of people were trapped by the rising flood waters in vehicles and buildings and had to be rescued. At least nine bridges were washed out; roads were washed away. Many buildings and crops were damaged and several buildings were destroyed.

7. Jun 27, 1998Flash Flood$3.0 million
   National Weather Service narrative

   Another round of thunderstorms with torrential rains produced additional flooding and contributed to ongoing flooding. Many roads were closed or remained closed. Forty families had to be evacuated from their homes. Before the thunderstorms moved away 10 inches or more of rainfall had occurred since early morning. Flood waters persisted in some areas for several days. The county was declared a state and federal disaster area.

8. Jun 29, 2012Thunderstorm Wind$1.4 million
   National Weather Service narrative

   An intense line of thunderstorms or Derecho moved across Knox County during the late afternoon of June 29th causing extensive damage. Winds were estimated to be as much as 65 mph. Over 50 percent of residents lost power during this event. Power was not completely restored for several days. Hundreds of trees were downed across the county along with many utility poles forcing the closure of some of roads and streets. Damage to homes and buildings was also extensive. Dozens of homes and buildings lost roofing or siding with many other homes damaged by fallen trees. Clean up costs were extensive. The clean up was hampered by an ongoing heat wave with afternoon temperatures in the…

9. Jan 1, 2005Flood, Knox$750,000
   National Weather Service narrative

   Heavy rain and runoff from snowmelt caused widespread lowland flooding in Ashland, Knox, Morrow, Richland Counties during the first two-thirds of January. January 2005 was the wettest January ever at Mansfield Lahm Airport with 6.08 inches of precipitation during the month. Rainfall totals from Knox County included; 7.51 inches at Greer; 7.97 inches at Fredericktown; 8.28 inches at Danville and 9.99 inches at Centerburg all in Knox County. In addition to this rain, extensive snowpack existed over northern Ohio at the beginning of the month. Temperatures in the 50s the first three days of the month caused a rapid snowmelt and brought area streams and creeks to bankfull just in time…

10. May 21, 2004Flash Flood$600,000
    National Weather Service narrative

    A line of severe thunderstorms moved across Knox County and dumped heavy rains on already saturated ground. Spotters reported between one and two inches of rain fell during the afternoon storms. Many streams and rivers in the county quickly went into flood forcing the closure of several roads. At least four bridges in the county were washed out. Flashing flooding near Apple Valley caused a retaining wall to fail. Many homes and businesses sustained damage from the flooding.

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

100°FJul 14, 1954

All-time low

−29°FJan 19, 1994

Warmest night

79°FMay 31, 2010

Coldest day

−10°F2 times, most recently Jan 19, 1994

Wettest day

5.18 inSep 14, 1979

Snowiest day

15.0 inFeb 6, 2026

Hottest year

2024mean 53.9°F

Coldest year

1972mean 47.3°F

Wettest year

199056.74 in

Driest year

196324.46 in

Snowiest season

53.2 in1959-60

Station Centerburg 2 Se (USC00331404), 1,205 ft elevation, 13.0 miles from the population centre. Daily records from 1950 to October 27, 2026; 97.7% 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 USC00331404.
• 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.