Iowa County

Every recorded tornado

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

More event types since 1996

Costliest events since 1996

1. May 10, 2003Hail$1.0 million
   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.

2. Apr 3, 2011Hail$1.0 million
   National Weather Service narrative

   Golf ball sized hail fell 2 miles south of Amana, IA around 625 pm CDT April 3.

3. Feb 24, 2007Ice Storm, Iowa$890,000
   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…

4. Jun 29, 1998Thunderstorm Wind$800,000
   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…

5. Jun 22, 2007Flash Flood$750,000
   National Weather Service narrative

   Eight to 12 inches of rain fell in the Marengo area, causing widespread major flash flooding throughout town. Water covered numerous roads, closing them or making them completely impassable. Some homes were surrounded by water up to 3 feet deep. The National Guard was activated to pump water from the town. Due to incredible local run-off, the Iowa River in Marengo rose from 11.4 feet to 17 feet in just 5 hours. (Flood stage is 14 feet.) The river eventually crested at 17.46 feet the morning of the 23rd. Some residents described the flooding of the town as worse than 1993, and in fact worse than had been seen for more than 40 years.

6. Jun 1, 2008Flood$747,000
   National Weather Service narrative

   The record crest on the Iowa River at Marengo occurred on June 12, 2008 at 21.38 feet. Flood stage is 14 feet.

7. Jun 19, 2009Flood$500,000
   National Weather Service narrative

   Heavy rains during the middle of the month resulted in the Iowa River at Marengo going above the moderate flood stage level of 15.5 feet on June 19th around 8 pm. It crested around 16.1 feet around 4 am June 20 and again around 16.2 feet around 730 am June 24. It finally fell below the moderate flood stage level around 230 am June 26.

8. May 10, 2003Hail$500,000
   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.

9. Aug 27, 2009Flood$500,000
   National Weather Service narrative

   Heavy rains during the last week of August resulted in the Iowa River at Marengo going above the moderate flood stage level of 15.5 feet on August 27th around 930 am. It crested around 16.87 feet around 630 am August 28. After falling off for a while, it rose to a secondary crest around 16.79 feet around 630 am August 30. It finally fell back below the moderate flood stage level around 1030 am August 31.

10. May 1, 2009Flood$500,000
    National Weather Service narrative

    Heavy rains during the last week of April resulted in the Iowa River at Marengo going above the moderate flood stage level of 15.5 feet on April 29th around 2 am. It crested around 17.64 feet around 9 pm April 30. It finally fell below the moderate flood stage level around 2 am May 7.

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°FAug 8, 1934

All-time low

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

Warmest night

82°FAug 17, 1983

Coldest day

−15°FFeb 3, 1996

Wettest day

6.15 inJun 15, 1982

Snowiest day

14.5 inFeb 2, 2011

Hottest year

1931mean 54.1°F

Coldest year

1917mean 45.6°F

Wettest year

199357.48 in

Driest year

198819.21 in

Snowiest season

58.0 in1959-60

Station Williamsburg 1E (USC00139067), 780 ft elevation, 3.3 miles from the population centre. Daily records from 1893 to October 27, 2026; 93.1% 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 USC00139067.
• 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.