Louisa County

Every recorded tornado

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

More event types since 1996

Costliest events since 1996

1. Jun 1, 2008Flood$19.0 million
   National Weather Service narrative

   The record crest on the Iowa River at Columbus Junction occurred on June 16, 2008 at 32.49 feet. Flood stage is 19 feet. The record crest on the Iowa River at Wapello occurred on June 14, 2008 at 32.15 feet. Flood stage is 20 feet.

2. Apr 30, 2003Hail$4.0 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. Jul 13, 2016Thunderstorm Wind$2.0 million
   National Weather Service narrative

   A trained spotter reported several limbs and trees were down in town. A few of the trees fell on homes.

4. Jul 29, 2016Flash Flood$2.0 million
   National Weather Service narrative

   A trained spotter reported heavy rains had produced washed out locations on gravel roads in the area.

5. Feb 24, 2007Ice Storm, Louisa$1.1 million
   National Weather Service narrative

   A widespread and crippling ice/snow storm affected eastern Iowa, northwest and western Illinois, and extreme northeast Missouri on February 24, 2007. This massive ice storm was the worst to affect the region since January 22-23, 1965. Ice accumulations of around one inch were common, with some reports to near two inches! To make matters worse, east winds gusting over 50 mph, combined with the heavy ice accumulation, brought down numerous tree branches and power lines, along with several thousand power poles. There were even whole trees crashing down from the weight of the ice. Widespread power outages occurred, affecting over 180,000 people, which lasted more than a week in some…

6. Jun 1, 2007Tornado$1.0 million
   National Weather Service narrative

   The tornado touched down on the southern edge of Grandview. It moved through the center of town intensifying in rural areas as it approached the county line. In Grandview, several homes sustained severe damage. North of Grandview, about 1.5 miles, a farm house was completely destroyed. Other homes and trees along the path sustained damage. The tornado crossed the Louisa-Muscatine county line just south of Fruitland, IA.|

7. Apr 30, 2003Hail$1.0 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…

8. May 10, 2003Tornado$1.0 million
   National Weather Service narrative

   Tornado developed in Henry County and moved ENE, entering Louisa County 1 mile west of Marsh at 1905 CST. Tornado continued moving ENE, passing 0.4 miles north of Marsh. Near Wapello the tornado began to dissipate but entered Wapello at the junction of G62 and K Avenue. The tornado crossed U.S. 61 and dissipated just short of the elementary school on North Cedar Street in Wapello. Path length was 11.5 miles in Louisa County and rated F0.

9. Apr 30, 2003Hail$1.0 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…

10. Jun 29, 1998Thunderstorm Wind$1.0 million
    National Weather Service narrative

    Supercell thunderstorms developed over Central Iowa and rapidly intensified into a long squall line which raced southeast over Eastern Iowa into Central Illinois. Numerous funnel clouds were sited along the leading edge of the storm and a few non-supercell tornadoes were masked within a large area of damaging winds. Straightline winds from 60 to over 120 mph produced the most serious damage with these storms and 8 counties in Eastern Iowa were declaired disaster areas. School-net stations measured winds at 69 mph in Cedar Rapids and 123 mph at Washington. Across the county warning area sustained winds of 70 to 80 mph ripped down trees, power lines, and windmills, and knocked over…

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

111°FMay 24, 1939

All-time low

−26°FJan 31, 2019

Warmest night

84°F3 times, most recently Aug 5, 1947

Coldest day

−8°F2 times, most recently Jan 15, 2024

Wettest day

7.47 inAug 17, 1939

Snowiest day

12.0 inJan 4, 1971

Hottest year

1946mean 54.8°F

Coldest year

2014mean 47.9°F

Wettest year

197355.91 in

Driest year

198817.34 in

Station New Boston Dam 17 (USC00116080), 547 ft elevation, 10.9 miles from the population centre. Daily records from 1938 to October 27, 2026; 93.8% 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 USC00116080.
• 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.