Henry County

Every recorded tornado

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

More event types since 1996

Costliest events since 1996

1. Jul 21, 2003Thunderstorm Wind$50.0 million
   National Weather Service narrative

   Also reported by law enforcement, spotters, and emergency managers in the southern part of the county. Extensive damage in Woodhull, Alpha, Nekoma, and Galva. Law enforcement reported zero visibility at the height of the storm on I-74 with cars blown into the ditches.

2. Apr 30, 2003Flash Flood$10.0 million
   National Weather Service narrative

   Supercell thunderstorms developed in the afternoon and evening north of a warm front that ran from Southern Iowa into Central Illinois. Three distinct supercells produced a majority of the wind, hail, and heavy rain reports from Jefferson County Iowa into Henry County Illinois. Mercer County Illinois was under tornado warnings on a continuous basis for 2 hours. Officials at a high school track meet in Aledo, Illinois ushered all students into the safety of the school resulting in no injuries. The training of the supercells from Louisa County Iowa to Henry County Illinois dumped heavy rain over the Edwards River and Pope Creek basins in Illinois with radar estimating 9 inches of…

3. Apr 19, 1996Tornado$10.0 million
   National Weather Service narrative

   10 Million in damage and 4 hospitalized as this tornado moved from Bishop Hill through Galva. At least 6 Million of damage was reported in the city limits of Galva where 150 homes were damaged, 26 received extensive damage, and 15 had to be destroyed. Extensive damage was also received to the city sewage treatment plant. A second, small and short lived tornado, did much less damage to the eastern part of town, most notably pushing over gravestones in a cemetery and downing trees.

4. Apr 19, 1996Tornado$10.0 million
   National Weather Service narrative

   10 Million in damage and 4 hospitalized as this tornado moved from Bishop Hill through Galva. At least 6 Million of damage was reported in the city limits of Galva where 150 homes were damaged, 26 received extensive damage, and 15 had to be destroyed. Extensive damage was also received to the city sewage treatment plant. A second, small and short lived tornado, did much less damage to the eastern part of town, most notably pushing over gravestones in a cemetery and downing trees.

5. May 13, 2010Flash Flood$5.0 million
   National Weather Service narrative

   Heavy rains resulted in widespread flash flooding of roads and highways across all of Henry County, especially the northwest half during the morning of May 13.

6. Apr 30, 2003Hail$500,000
   National Weather Service narrative

   Supercell thunderstorms developed in the afternoon and evening north of a warm front that ran from Southern Iowa into Central Illinois. Three distinct supercells produced a majority of the wind, hail, and heavy rain reports from Jefferson County Iowa into Henry County Illinois. Mercer County Illinois was under tornado warnings on a continuous basis for 2 hours. Officials at a high school track meet in Aledo, Illinois ushered all students into the safety of the school resulting in no injuries. The training of the supercells from Louisa County Iowa to Henry County Illinois dumped heavy rain over the Edwards River and Pope Creek basins in Illinois with radar estimating 9 inches of…

7. May 10, 2003Thunderstorm Wind$400,000
   National Weather Service narrative

   A strong spring storm system moved through the Mississippi valley during the late afternoon and evening hours producing widespread severe weather. In an unprecedented move, WFO Quad Cities held a press conference the day before to warn of a high probability of significant tornadoes in the afternoon and evening hours of Saturday May 10th, with the area most at risk south of a Keosauqua, Iowa to Princeton, Illinois line. Supercell thunderstorms developed and continued into the evening hours spawning several long track tornadoes and produced copious amounts of large hail. Luckily, most of the tornado tracks were in open country and therefore damage was minimized. After dark, a severe…

8. May 10, 2003Tornado$400,000
   National Weather Service narrative

   Developed 1 mile East of Galva and moved northeast, passing 0.25 miles SE of Kewanee. Tornado continued northeast and exited into Bureau County 2.8 miles ENE of Kewanee at 2010 CST. Path length was 9.8 miles and rated F0.

9. Apr 30, 2003Thunderstorm Wind$400,000
   National Weather Service narrative

   Supercell thunderstorms developed in the afternoon and evening north of a warm front that ran from Southern Iowa into Central Illinois. Three distinct supercells produced a majority of the wind, hail, and heavy rain reports from Jefferson County Iowa into Henry County Illinois. Mercer County Illinois was under tornado warnings on a continuous basis for 2 hours. Officials at a high school track meet in Aledo, Illinois ushered all students into the safety of the school resulting in no injuries. The training of the supercells from Louisa County Iowa to Henry County Illinois dumped heavy rain over the Edwards River and Pope Creek basins in Illinois with radar estimating 9 inches of…

10. Mar 12, 2006Thunderstorm Wind$300,000
    National Weather Service narrative

    A bow echo interacted with a surface boundary over Atkinson and produced a ducted downburst over a narrow path of about 1 mile. About 12 homes sustained varying amounts of damage with many trees either uprooted or damaged. An RV wasflipped onto its side.At the Atkinson Grain & Fertilizer plant a 100 foot leg was torn away and dropped on the railroad tracks where it was hit by a slow moving train several hours later.

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

107°FJul 24, 1901

All-time low

−25°F2 times, most recently Jan 31, 2019

Warmest night

81°FJul 20, 2019

Coldest day

−13°FJan 18, 1994

Wettest day

6.57 inAug 25, 1898

Snowiest day

16.0 inJan 3, 1971

Hottest year

2012mean 54.7°F

Coldest year

1978mean 47.5°F

Wettest year

189856.93 in

Driest year

200519.24 in

Snowiest season

52.9 in1978-79

Station Geneseo (USC00113384), 639 ft elevation, 7.0 miles from the population centre. Daily records from 1895 to October 26, 2026; 99.4% 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 USC00113384.
• 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.