Ralls County

Every recorded tornado

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

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.

Mapped landslides

Mapped by MO DNR (13).

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 9, 2021Thunderstorm Wind$1.3 million
   National Weather Service narrative

   An NWS storm survey discovered a macroburst that first initiated to the north of Rensselaer, MO. This macroburst caused extensive tree damage in town, especially on the western side of Rensselaer where several large branches and trees were snapped or uprooted and a few roofs sustained damage. Winds in this area were determined to be around 80 mph. The large swath of damaging winds then pushed south towards Mark Twain State Park. Extensive tree damage was noted in the state park. In addition, the Blackjack Marina sustained quite a bit damage from straight line winds around 80 mph. These winds were strong enough to cause damage to several boats, damage to the metal roofing of the…

2. Jul 29, 2008Flood$200,000
   National Weather Service narrative

   Rainfall of 7 - 10 inches fell across North Central Missouri causing flooding at Mark Twain Lake and along the Salt River. This represented the first flooding of the Salt River since the completion of Clarence Cannon Dam which created Mark Twain Lake in 1984. The crest at New London represented the 8th highest crest of record, resulting in the flooding of numerous farm houses and state roads. Thirty families had to be evacuated from their homes due to the flooding. At least 30 roads had to be closed. Agricultural losses were estimated at $10 million. Initial public assistance damage estimates were put at $200,000.

3. Jun 3, 2008Flood$55,000
   National Weather Service narrative

   The Mississippi River at Saverton, MO crested at 27.97 feet on 6/18/2008. This is the second highest crest ever recorded. Ten homes in the Saverton area were flooded. The lock and dam at Saverton was over topped by the river. Highway 79 was closed at a couple of locations. There were no other towns affected as the rest of the county along the river is open flood plain. The County estimated public infrastructure damage at $55,000. No agricultural losses were reported.

4. Jun 17, 2022Thunderstorm Wind$50,000
   National Weather Service narrative

   Widespread wind damage across Ralls County, especially in Center, New London and portions of Hannibal in northeastern Ralls County. There were numerous tree limbs blown down as well as power lines. In Center, a tree was blown down onto a house causing moderate roof damage. In New London, another large tree was blown down onto a house causing moderate roof damage. A tree was blown down onto Highway HH north of New London.

5. May 30, 2008Tornado$30,000
   National Weather Service narrative

   A tornado initially formed near the intersection of Highway 19 and County Road 209. Power pole and tree damage was noted at this location. The tornado moved east northeast and caused more tree damage about 3/4 mile south of Highway 19 and Clarence Cannon Lane. The tornado crossed Highway P about 1 mile south of Center. Large power poles were bent over about 20 degrees at this location. The tornado moved east northeast and damaged a modular home and a machine shed near Kingbird and Vesper Drive. About 100 yards east of this location a mobile home was turned onto its side.

6. Feb 29, 2000Thunderstorm Wind$20,000
   National Weather Service narrative

   Thunderstorm wind gusts destroyed a mobile home and caused some roof damage to another home. Several trees were also downed in the area.

7. Jun 20, 2000Tornado$10,000
   National Weather Service narrative

   The County Sheriff reported a brief tornado west of Rensselaer. Trees were uprooted and a barn heavily damaged.

8. Apr 12, 2013Flood$1,000
   National Weather Service narrative

   The Mississippi River rose to major flood levels along the border of Ralls County. The river crested on the 21st through 22nd, but continued above flood stage into May. Damage was limited to a few roads closed and flooding of agricultural lowlands.

9. May 26, 2013Flood$1,000
   National Weather Service narrative

   The Mississippi River began May at major flood levels. It slowly fell to below flood stage on the 24th, but then rose again over flood stage on May 26th and hit major levels by the end of the month. Damage was limited to some flooded roads and farmland.

10. Oct 24, 2021Thunderstorm Wind$1,000
    National Weather Service narrative

    Thunderstorm winds blew down a large tree near the Ralls County Sheriff's office in New London.

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

114°FJul 14, 1954

All-time low

−21°F3 times, most recently Dec 23, 1989

Warmest night

85°F2 times, most recently Aug 22, 1936

Coldest day

−10°FDec 22, 1989

Wettest day

5.92 inJul 20, 1949

Snowiest day

14.5 inFeb 2, 2011

Hottest year

1934mean 56.9°F

Coldest year

2014mean 50.0°F

Wettest year

198161.22 in

Driest year

195620.59 in

Snowiest season

63.1 in1977-78

Station Hannibal Wtr Wks (USC00233601), 712 ft elevation, 11.1 miles from the population centre. Daily records from 1933 to October 27, 2026; 97.4% 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 USC00233601.
• 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.