Chickasaw County

Every recorded tornado

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

More event types since 1996

Costliest events since 1996

1. Jun 7, 2008Flood$600,000
   National Weather Service narrative

   Highways 18 and 63 were closed in spots from flood waters. A Local Area Emergency (LAE) was issued for the county based on requests early Sunday morning June 8. Main roads were mostly open, but secondary and township roads were under water. The Cedar River caused flooding in parts of Nashua where sand bagging efforts were unable to save a water main from breaking and cutting off the towns water supply. Rainfall totals of 6 to 7 inches were reported during the weekend of June 7-8.

2. Aug 28, 2021Flood$500,000
   National Weather Service narrative

   Numerous roads were closed across Chickasaw County because of flood waters in the Ionia area. The East Fork of the Wapsipinicon River went out of its banks forcing officials to close U.S. Highway 18 near Fredericksburg. A train attempting to cross the Wapsipinicon River southwest of New Hampton derailed causing officials to evacuate nearby residents when one of the tank cars leaked some anhydrous ammonia.

3. Jul 18, 1999Flash Flood$500,000
   National Weather Service narrative

   As much as 8 inches of rain caused flash flooding over portions of northeast Iowa. Hardest hit were Rockford and Nora Springs (Floyd County) where an earthen dike washed away and a dam was breached. Both communities suffered extensive damage to homes and businesses due to what was described as the worst flooding in years. Numerous rural roads throughout the area were washed out, while corn and soybean fields were underwater. A man died when his car was swept away, attempting to cross a flooded bridge near Rudd (Floyd County).

4. Jun 18, 1998Thunderstorm Wind$500,000
   National Weather Service narrative

   A line of severe thunderstorms knocked down numerous trees and power lines across northeast Iowa. The town of Nashua was hardest hit as straight-line winds, estimated as high as 120 mph, damaged over 70 homes and blew down approximately 1000 trees. Five businesses in Nashua sustained damage and a 100 foot concrete silo was toppled. A man was also injured when his mobile home was destroyed.Farm outbuildings were damaged and trees blown down in other areas of Chickasaw County and around Decorah in Winneshiek County.

5. Jul 22, 2017Flash Flood$350,000
   National Weather Service narrative

   Heavy rains of 4 to 8 inches caused flash flooding to occur across the southern sections of Chickasaw County. Flood waters from two small creeks covered U.S. Highway 18 west of Fredericksburg. The flood waters prompted sandbagging to be done in New Hampton. Numerous roads across the county sustained damage during the flooding.

6. Jul 20, 1999Flash Flood$350,000
   National Weather Service narrative

   Thunderstorms dropped torrential rains on northeast Iowa, which caused a second round of flash floods in as many days. Numerous highways were either closed or remained closed due to high water.

7. Jul 19, 1999Flood, Chickasaw$350,000
   National Weather Service narrative

   The Cedar River experienced record flooding due to excessive rainfall amounts. On the 19th, the river crested at 18.26 feet at Charles City (Floyd County). Two days later on the 21st, the river had an all-time record crest at Charles City of 22.80 feet. Cooperative observer rainfall reports from the 19th through the 21st included 11.81 inches at Charles City, 10.75 inches at Osage (Mitchell County) and 11.85 inches at New Hampton (Chickasaw County).Nearly every creek, stream and river in Chickasaw and Floyd Counties was bankfull or flooding during the National Weather Service storm survey. Many roads were impassable. There was extensive evidence of flash flooding from heavy rains…

8. Dec 15, 2021Tornado$330,000
   National Weather Service narrative

   The second tornado of the night in Chickasaw County formed southwest of Alta Vista and moved northeast before crossing into Howard County along County Line Road just east of the Little Wapsipinicon River. This tornado was rated EF0. The tornado damaged a greenhouse facility, otherwise, damage was limited to trees.

9. Dec 15, 2021Tornado$255,000
   National Weather Service narrative

   An EF1 tornado formed west of North Washington and moved to northeast for about 4 miles before dissipating. The tornado damaged trees and some farm outbuilding along its path.

10. Nov 10, 1998High Wind, Chickasaw$150,000
    National Weather Service narrative

    One of the most powerful low pressure systems in 25 years caused hurricane force winds with gusts up to 90 mph. Widespread damage occurred to vehicles, signs, buildings and trees, while thousands were left without power for hours. A barn collapsed near Waukon, trapping a man inside, but only minor injuries were sustained.

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

110°F2 times, most recently Jul 14, 1936

All-time low

−34°F2 times, most recently Jan 15, 1963

Warmest night

82°FJul 8, 1897

Coldest day

−17°F2 times, most recently Feb 2, 1996

Wettest day

7.10 inJul 21, 1999

Snowiest day

15.0 inNov 30, 1934

Hottest year

1931mean 51.2°F

Coldest year

2014mean 41.1°F

Wettest year

201865.67 in

Driest year

191016.69 in

Snowiest season

74.6 in2018-19

Station New Hampton (USC00135952), 1,148 ft elevation, 1.6 miles from the population centre. Daily records from 1897 to October 27, 2026; 97.0% 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.

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 USC00135952.
• 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.