Arnold

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond this area.
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.

Flood insurance figures are for Jefferson County, the county that contains Arnold.

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 in Jefferson County, the county that contains Arnold.

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.

The drought index is for Jefferson County, the county that contains Arnold.

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 city centre.
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

Landslides mapped in Jefferson County.

Mapped by NASA (2).

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. Jul 1, 2015Flash Flood$4.0 million
   National Weather Service narrative

   Up to 7 inches of rain fell in a short amount of time onto already saturated soils causing flash flooding. The main band of heavy rain extended from northwest of Cedar Hill southeastward to southeastern Jefferson County, south of Festus. Four vehicles were swept off of Meyer Road, just west of intersection with U.S. Highway 67, when Buck Creek rose well above its banks. All four vehicles were swept downstream but only two were occupied, the other two had been in a nearby parking lot. Two bodies were found further downstream, a 35 year old female and a 50 year old female. Authorities say that the owners of the other two vehicles have been accounted for. Several rescues had to be…

2. Dec 28, 2015Flood$2.2 million
   National Weather Service narrative

   Between 5 and 8 inches of rain fell across Jefferson County during a 2 day period. All of this rain caused the creeks and rivers to rise. The Meramec River and Big River went into major flood with several points cresting at record levels. Forty four homes were destroyed, 975 buildings had major damage and 308 buildings had minor damage from the river flooding, with Arnold being the worst hit in Jefferson County. Also, the High Ridge District 2 water treatment plant was inundated by the flood waters on December 30th, cutting off water supply to at least 20,000 residents. Damage estimates so far were around $2.2 million.

3. Mar 14, 2025Tornado$825,000
   National Weather Service narrative

   At approximately 9:18 PM a tornado began just south of Morse Mill, MO causing damage to trees and homes as it moved northeast. The worst damage in Jefferson County occurred in the southwest corner of Arnold where the roof of a residence was torn off on Shelley Lynn Drive. The tornado then passed into south St. Louis County. In Jefferson County the tornado had a path length of 20.9 miles and a maximum path width of 850 yards. It was rated an EF2.

4. May 7, 2000Flash Flood$500,000
   National Weather Service narrative

   Rainfall up to 8 inches fell on western Jefferson County causing widespread flash flooding. A joint Federal -State Damage Assessment Team concluded that 1 structure was destroyed, 9 suffered major damage, 42 minor damage and another 7 were affected. Some areas, especially along the Big River, were spared major damage because of buyouts that were made after flooding in 1993.

5. Aug 3, 2022Flash Flood$120,000
   National Weather Service narrative

   Up to five inches of rain fell in a short amount of time causing flash flooding in the far northern portions of the county. Numerous roads were flooded including Highway 141. There were multiple water rescues on Highway 141, but no injuries were reported. Also, several water evacuations were performed at homes near the intersection of Romaine Creek Road and Konert Road. Twenty four home sustained minor flood damage.

6. Jul 2, 2000Flash Flood$100,000
   National Weather Service narrative

   Heavy rain caused flash flooding across northeast Jefferson County. Glaize Creek flooded affecting a narrow area north of new Highway M from just west of Antonia to Highway 61-67 at Barnhart. Several businesses flooded, including a couple automobile repair shops. Seven vehicles from the shops were washed away by the flood water. Six people had to be rescued from flooded vehicles. Several county roads and a couple of bridges were damaged by the flood water.

7. Apr 18, 2024Tornado$100,000
   National Weather Service narrative

   The tornado touched down in a subdivision southwest of Eureka in rural St. Louis County where it caused minor tree damage. The tornado moved east across the Meramec River into Jefferson County where it damaged two large metal outbuildings and snapped wooden electrical poles on Twin River Rd Between the Meramec and Big Rivers. The tornado continued to the east where it caused tree damage before lifting southeast of High Ridge.

8. Jun 21, 1997Thunderstorm Wind$100,000
   National Weather Service narrative

   County sheriff reported numerous trees and power lines down. About a dozen homes were damaged mainly from the falling trees. About 10 vehicles were also damaged by the falling trees.

9. Nov 4, 2024Flash Flood$50,000
   National Weather Service narrative

   Flash flooding resulted in cropland, yard, basement, and road flooding around Jefferson County. Water flooded residences in a mobile home park in High Ridge, with several homes and mobile homes being evacuated. Multiple water rescues were also reported in House Springs.

10. Apr 21, 1999Lightning$35,000
    National Weather Service narrative

    An early morning lightning strike caused considerable damage at the Special Services Cooperative office in Hillsboro. The strike destroyed the telephone system, electric boxes, and blew out 5 windows. The building shook hard enough to cause plaster to fall from the walls.

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

115°FJul 14, 1954

All-time low

−18°FJan 20, 1985

Warmest night

86°FJul 25, 2012

Coldest day

−5°FDec 24, 1983

Wettest day

8.64 inJul 26, 2022

Snowiest day

12.4 inMar 24, 2013

Hottest year

2012mean 61.2°F

Coldest year

1978mean 53.4°F

Wettest year

201561.24 in

Driest year

195320.59 in

Snowiest season

66.0 in1977-78

Station St. Louis Lambert International Airport (USW00013994), 531 ft elevation, 22.6 miles from the city centre. Daily records from 1938 to October 27, 2026; 100.0% 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.

Declarations for Jefferson County.

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.

• 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 USW00013994.
• 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.