Oregon County

Every recorded tornado

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

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.

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.

Costliest events since 1996

1. Apr 29, 2017Flash Flood$4.0 million
   National Weather Service narrative

   Numerous county roads and bridges were damaged by flash floods. Several campgrounds and river access areas were severely damaged across the county. This report will contain the total dollar estimate for flood damage to infrastructure, businesses, and homes across Oregon County. $3M in damages were reported to roads alone in the county.

2. Nov 5, 2005Tornado$1.5 million
   National Weather Service narrative

   A National Weather Service storm survey team revealed that an F-2 tornado touched down 9 miles east of Thayer near Highway V. The tornado continued on a path 300 yards wide to 8 miles northeast of Myrtle. Two mobile homes were destroyed and several other homes were heavily damaged along the tornado path.

3. May 8, 2009Thunderstorm Wind$1.0 million
   National Weather Service narrative

   Sixty to 80 mph wind gusts impacted all of Oregon County. Significant tree damage was observed countywide, while numerous outbuildings and homes sustained damage. It was relayed to the National Weather Service that several homes in the community of Koshkonong had windows that were blown out. Roof damage was widespread in all communities of Oregon County.

4. Mar 18, 2008Flash Flood$1.0 million
   National Weather Service narrative

   Eight to nine inches of rain fell over Oregon County. Widespread flooding occurred along all low areas that typically experience flooding during periods of excessive rainfall.

5. Apr 25, 2011Flash Flood$1.0 million
   National Weather Service narrative

   Widespread flooding of low water crossings and rural routes were reported.||The total cost estimate for flooding damages for Oregon County for this entire episode has been included. This includes roads, bridges, and structures which were affected.

6. Mar 14, 2025Tornado$800,000
   National Weather Service narrative

   A 24 mile long tornado path was determined by a combination of NWS survey, storm reports, and satellite damage to have moved from just north of Koshkonong to 2 miles north of Alton before lifting 8 miles northeast of Alton. Maximum width was approximately a half mile wide though it was likely considerably narrower in places. While much of the path was to trees along with several outbuildings, the tornado damaged a few homes including a south facing ground level home off County Road 402 where it caused EF3 damage. The track continued northeast of Alton into the Mark Twain National Forest with satellite detecting an intermittent path of uprooted trees to near the Eleven Point River…

7. Dec 28, 2015Flash Flood$500,000
   National Weather Service narrative

   Highway 142 was closed near the Eleven Point River. Numerous low water crossings across the county were flooded. Several county roads were damaged. Several campground areas along the Ozarks Scenic Riverways were damaged. This storm report will contain the damage estimates for the entire county for this event.

8. Mar 14, 2025Tornado$400,000
   National Weather Service narrative

   This is the beginning of a long-track EF-3 tornado that began south of Rover, MO and tracked northeast before lifting in southern Reynolds County. The peak wind speed was 165 mph with a maximum width of 800 yards. The tornado initially touched down around 2 miles northeast of Brandsville, then moved south of Rover where it pushed two homes off their foundation before continuing northeast through wooded areas. The tornado then took the roof off another home but left internal walls intact along Highway DD and again at the north end of County Road 331. It was also at this point that it caused the collapse of a pair of new high voltage transmission line metal support polls rated to…

9. Nov 1, 2022Drought, Oregon$350,000
   National Weather Service narrative

   Drought conditions improved across Morgan County by the end of November. The US Drought Monitor indicated that Moderate (D1) drought conditions remained at the end of the month after several rainfall events helped ease drought conditions below severe (D2) drought levels. Impacts across the region were primarily felt in larger scale agriculture with farm and stock ponds low but improved. Dry conditions caused grasses to dry and significantly impact hay production causing losses in hay cutting. Many farmers saw impacts to row crops such as soy beans, corn and other specialty crops.

10. May 26, 2024Tornado$200,000
    National Weather Service narrative

    A NWS storm survey concluded that an EF-1 tornado occurred in far southeast Oregon County to the east of Myrtle. Two homes suffered siding damage, five barns/outbuildings were destroyed, along with numerous trees suffering damage that ranged from limb damage to being uprooted along County Road 288 before the tornado crossed the Eleven Point River near the Myrtle Access and crossed into Ripley County north of County Road 286. One injury was reported. Damage cost estimates only include the Oregon County portion of the tornado track.

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

110°F3 times, most recently Jul 16, 1980

All-time low

−24°FFeb 2, 1951

Warmest night

82°F2 times, most recently Jul 16, 1936

Coldest day

4°FJan 12, 1918

Wettest day

12.36 inDec 3, 1982

Snowiest day

9.0 in2 times, most recently Nov 27, 1980

Hottest year

1921mean 61.8°F

Coldest year

2014mean 53.9°F

Wettest year

201570.68 in

Driest year

198026.55 in

Snowiest season

23.0 in1976-77

Station Mammoth Spring (USC00034572), 502 ft elevation, 9.0 miles from the population centre. Daily records from 1904 to October 26, 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 USC00034572.
• 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.