Plymouth County

Every recorded tornado

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

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. Mar 13, 2019Flood$2.3 million
   National Weather Service narrative

   Up to 25 gravel roads were under water across Plymouth County. Other flooding resulted in extensive damage to public infrastructure including numerous county and township roads, culverts, and some bridges.

2. Jun 21, 2024Flood$1.6 million
   National Weather Service narrative

   Rainfall amounts across Plymouth County from June 20-22 ranged from only a few hundredths across southern areas to around 2 inches across northern areas. Farther north and upstream, 6 to 10 inches of rain fell across portions of southeast South Dakota and northwest Iowa, with locally higher amounts near 12 inches. This rainfall resulted in major to record flooding along the Big Sioux and Floyd Rivers and extensive overland flooding along the adjoining flood plain. ||During peak flooding, areas between the Big Sioux River and Iowa Highway 12 were evacuated. The Willow Creek Campground in Le Mars was also evacuated. There were at least two water rescues, including 14 individuals.…

3. Jun 16, 2014Flood$500,000
   National Weather Service narrative

   Repeated heavy rains caused record flooding of the Big Sioux River. Farmland and other lowlands including numerous roads were flooded. Some roads were damaged, and some secondary roads were washed out. Several homes, businesses, and farm buildings were flooded and damaged. A levee breach caused additional flooding in the city of Akron, forcing the evacuation of several residences on the west side of Iowa Highway 12 while the levee was being repaired. The river crested at a record 9.59 feet above flood stage at Akron on June 18th.

4. Jun 19, 1996Flood, Plymouth$300,000
   National Weather Service narrative

   Rainfall of 5 to 15 inches during a 30 hour period caused widespread lowland, crop, urban, and river flooding. Rivers and streams including the Big Sioux, Little Sioux, West Fork Little Sioux, and Floyd Rivers were over flood stage for 2 to 6 days. The flooding caused widespread destruction of crops, drowned livestock, flooded and washed out roads, and flooded homes and other buildings, damaging contents.

5. Jan 20, 2010Ice Storm, Plymouth$200,000
   National Weather Service narrative

   Freezing rain produced ice accumulations of a quarter to a half inch. Travel and walking were made extremely hazardous and difficult. Damage to trees and power lines was reported, including more than 200 utility poles brought down by the ice, and there were scattered power outages.

6. Apr 15, 2017Hail$125,000
   National Weather Service narrative

   Numerous reports of large hail up to half dollar size caused plenty of damage mainly to windows of homes and vehicles.

7. Sep 24, 2002Thunderstorm Wind$100,000
   National Weather Service narrative

   According to a report from the county extension officer, small hail, accompanied by gusty winds, caused damage to corn and soybean crops.

8. Jun 19, 1996Hail$100,000
   National Weather Service narrative

   Hail damaged cars and crops.

9. Jun 23, 2003Thunderstorm Wind$100,000
   National Weather Service narrative

   Thunderstorm winds caused widespread tree damage, including several trees and numerous large limbs and branches blown down. Tree debris damaged the roofs of at least three homes. The siding of a manufacturing business building was ripped off by the wind. Power lines were downed by wind and falling tree debris, resulting in power outages.

10. Apr 15, 2017Hail$75,000
    National Weather Service narrative

    Hen egg to baseball size hail damaged vehicles and homes.

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°FJul 17, 1936

All-time low

−37°FJan 12, 1912

Warmest night

85°FAug 18, 1936

Coldest day

−17°FDec 22, 1989

Wettest day

8.76 inAug 29, 1985

Snowiest day

15.2 inJan 22, 1982

Hottest year

1931mean 53.2°F

Coldest year

2009mean 43.5°F

Wettest year

195141.97 in

Driest year

197613.02 in

Snowiest season

67.1 in1983-84

Station Le Mars (USC00134735), 1,299 ft elevation, 4.0 miles from the population centre. Daily records from 1896 to October 27, 2026; 98.0% 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 USC00134735.
• 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.