| May 2004 | Hail | Spencer | $500,000 | Large hail caused widespread damage to vehicles, windows, and roofs. Crop damage was also extensive in the area with over one hundred thousand acres of corn, beans, and other small grain crops affected during this storm and another hail storm which occurred later in the day. The amount of crop damage was not known. |
| May 2004 | Hail | Spencer | $500,000 | Large hail damaged vehicles, broke windows, and damaged roofs and siding. Crop damage was also extensive with over one hundred thousand acres of corn, bean, and other small grain crops affected during this storm and another hail storm in the area earlier in the day. The amount of crop damage was not known. Property damage was in addition to the damage from the earlier storm. |
| June 2001 | Thunderstorm Wind | Spencer | $300,000 | Thunderstorm winds caused widespread tree damage, with several streets blocked by fallen trees. Some vehicles were damaged by tree debris. The winds tore a wall and part of the roof from a racquet club building. Power lines and poles were blown down, resulting in a one hour power outage which affected almost all of the city of Spencer. |
| August 1993 | Thunderstorm Wind | Spencer | $50,000 | no account filed |
| July 2010 | Thunderstorm Wind | Spencer | $20,000 | Thunderstorm winds caused tree damage, including a large tree that fell on and damaged a house. |
| May 2012 | Thunderstorm Wind | Spencer | $10,000 | Thunderstorm winds caused tree damage, including numerous trees blown down. The winds also blew out windows. |
| October 2019 | Flood | Spencer | $5,000 | Rainfall from October 1-5 totaled 4.81 inches at Lake Park, 4.61 inches at Spirit Lake, 3.85 inches 3 miles south-southeast of Lake Park and 3.65 inches at Spencer. The Little Sioux River at Spencer (gage site SPWI4) climbed into minor flood and crested 1.65 feet above flood stage on October 7. Flooding impacts were generally to agricultural areas, with water inundating the City Park in Spencer. Property and crop damage costs are rough estimates. |
| June 1999 | Thunderstorm Wind | Spencer | $5,000 | Thunderstorm winds blew down signs and caused tree damage. |
| June 1994 | Hail | Spencer | $5,000 | no account filed |
| June 1994 | Hail | Spencer | $5,000 | no account filed |
| June 1994 | Thunderstorm Wind | Spencer | $5,000 | no account filed |
| September 1994 | Hail | Spencer | $5,000 | no account filed |
| July 2025 | Thunderstorm Wind | Spencer | - | Thunderstorm winds uprooted several trees throughout town. |
| July 2025 | Thunderstorm Wind | Spencer | - | Spotty minor tree damage occurred across town with scattered small limbs blown down. |
| April 2024 | Flood | Spencer | - | The Little Sioux River at Spencer, IA rose above flood stage on the evening of April 30th with minor flooding continuing into May. |
| July 2024 | Flood | Spencer | - | Flooding continued from June on the Little Sioux River at Spencer, with declining river levels. The river fell below flood stage on the morning of July 18th. |
| May 2024 | Flood | Spencer | - | The Little Sioux River at Spencer rose above flood stage the afternoon of May 21st, cresting around 2.06 feet above flood stage (12.06 feet) on May 24th. The river remained above flood stage into the month of June. |
| May 2024 | Flood | Spencer | - | Flooding on the Little Sioux River near Spencer continued from late April, cresting around 3.34 feet above flood stage (13.34 feet) on May 10th. The river then briefly fell below flood stage the afternoon of May 17th. |
| June 2024 | Thunderstorm Wind | Spencer | - | Several tree limbs were downed by thunderstorm wind gusts. |
| June 2024 | Thunderstorm Wind | Spencer | - | Spotter estimated a wind gust of 60 mph based on tree damage on the west side of Spencer. |
| June 2024 | Flood | Spencer | - | The Little Sioux River at Spencer continued above flood stage from May, cresting around 2.17 ft above flood stage (10.17 ft) on June 2nd. This crest is in the Moderate Stage. The river then fell below flood stage on the evening of June 14th. |
| June 2024 | Flood | Spencer | - | The Little Sioux River at Spencer rose above flood stage the morning of June 17th, cresting around 12.2 feet above flood stage (22.2 feet) on June 22nd. The crest value was determined via high water mark due to a river gauge outage. This crest is in the Major Stage and broke the previous record. Significant flooding was observed within the city of Spencer itself. The river stayed above flood stage into July. For a more comprehensive description of flood damage, please see other entries for Clay County. |
| April 2023 | Flood | Spencer | - | The Little Sioux River at Spencer rose above flood stage on the evening of April 3rd before cresting around 0.06 feet above flood stage (10.06 feet) on April 4th. The river then fell below flood stage on the evening of April 4th. |
| May 2023 | Flood | Spencer | - | The Little Sioux River at Spencer, IA rose above flood stage on the morning of May 14 before cresting around 0.89 feet above flood stage (10.89 feet) on May 16th. The river then fell below flood stage on the morning of May 18th. |
| May 2022 | Thunderstorm Wind | Spencer | - | A thunderstorm wind gust downed numerous 2 to 3 inch tree branches. |
| August 2022 | Thunderstorm Wind | Spencer | - | A large, but decaying tree, was downed by thunderstorm winds. |
| December 2021 | Thunderstorm Wind | Spencer | - | Numerous large trees were downed by thunderstorm winds in Spencer. |
| April 2020 | Flood | Spencer | - | A continuation of minor flooding from March, the Little Sioux River at Spencer (gage site SPWI4) began the month at 0.82 feet above flood stage, with a slow and steady fall below flood stage by April 3. Flooding occurred in agricultural areas southeast of Spencer, as well as some inundation of the Spencer City Park. |
| May 2020 | Flood | Spencer | - | The Little Sioux River at Spencer (gage site SPWI4) spent most of the last half of the month in minor flooding, with a crest of 2.05 feet above flood stage on May 28. Flooding occurred in agricultural areas southeast of Spencer, as well as some inundation of the Spencer City Park. |
| March 2020 | Flood | Spencer | - | With rainfall of 1.11 inches at Lake Park and 0.88 inches at Spencer, the Little Sioux River at Spencer (gage site SPWI4) returned above flood stage at the end of the month. The river crested 1.04 feet above flood stage on March 30, and remained at minor flood stage at the end of the month. |
| March 2020 | Flood | Spencer | - | The Little Sioux River at Spencer (gage site SPWI4) rose above flood stage on March 6, and crested 1.70 feet above flood stage on March 10. Significant amounts of agricultural land were flooded. |
| June 2020 | Flood | Spencer | - | Rainfall of 1.34 inches at Spencer and 1.30 inches 4 miles northwest of Milford on June 8-9 brought the Little Sioux River at Spencer (gage site SPWI4) briefly into minor flood, with a crest of 0.25 feet above flood stage on June 11. Minor flooding occurred in the Spencer City Park. |
| June 2019 | Flood | Spencer | - | A continuation of flooding from May, the Little Sioux River at Spencer (gage site SPWI4) began the month at 3.76 feet above flood stage. Significant amounts of agricultural land remained flooded, and further impeded spring planting. |
| June 2019 | Hail | Spencer | - | Pea to nickel size with occasional quarter size. Strong winds accompanied hail. |
| March 2019 | Flood | Spencer | - | Snow melt and heavy rainfall (measured 1.27 inches at Spencer) resulted in significant flooding of agricultural lands and numerous roads around Spencer including U.S. Highways 18 and 71. The Little Sioux River at Spencer (gage site SPWI4) reached the third highest stage on record cresting 7.45 feet above flood stage on March 15. The river remained in minor flood stage at the end of the month. |
| May 2019 | Flood | Spencer | - | This is a continuation of flooding from April. The Little Sioux River at Spencer (gage site SPWI4) had an early month crest at 1.40 feet above flood stage on May 2, before falling below flood stage on May 16. Late month rains pushed the river back over flood stage on May 23, reaching a crest in moderate flood stage of 4.02 feet above flood stage on May 30. Significant agricultural flooding persisted, with no opportunity for spring planting throughout the flood plain. The river remained at moderate flood stage at the end of the month. |
| April 2019 | Flood | Spencer | - | Runoff from occasional precipitation in early April returned significant flooding of agricultural lands. The Little Sioux River at Spencer (gage site SPWI4) crested at 2.08 feet above flood stage on April 13. The river remained in minor flood stage at the end of the month. |
| March 2018 | Flood | Spencer | - | Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along upper portions of the Little Sioux River. River levels reached 2.3 feet above flood stage at Spencer (gage site SPWI4) by the end of the month. |
| April 2018 | Flood | Spencer | - | Minor flooding continued from March 2018, with the river at Spencer (gage site SPWI4) returning below flood stage on April 4. |
| April 2018 | Flood | Spencer | - | Flooding returned to the Little Sioux River in mid-April, and was generally minor with impacts limited to near river agricultural areas. Periodic rain and snow brought 1 to 3 inches of liquid equivalent in the week prior to a return to flood stage at Spencer (gage site SPWI4) on April 14. The river crested in minor flood stage (3.2 feet above flood stage) on April 24, inundating a large amount of pasture and crop land along the flood plain as well as the city park in Spencer. The river remained in minor flood stage at the end of the month. |
| July 2018 | Thunderstorm Wind | Spencer | - | Large trees uprooted in town. |
| March 2018 | Flood | Spencer | - | Heavy rainfall along with snow melt caused minor flooding of lowland agricultural areas and Spencer city parks along upper portions of the Little Sioux River. The river reached a crest of 1.8 feet above flood stage at Spencer (gage site SPWI4) on March 7. |
| March 2018 | Flood | Spencer | - | Periods of rainfall along with snow melt through mid to late March caused an extended period of minor flooding on the Little Sioux River along lowland agricultural areas as well as the Spencer city park. The highest of multiple crests reached 1.6 feet above flood stage at Spencer (gage site SPWI4) on March 16. |
| July 2018 | Flood | Spencer | - | Capping off nearly a month continuously above flood stage, water levels crested in moderate flood stage early in the month, with multiple crests at minor flooding levels during the month. Numerous county and township roads were impacted by water early in the month, including county road B40. Significant amounts of crop and pasture land as well as city parks in Spencer were severely impacted by moderate flooding as river levels climbed to 4.7 feet above flood stage at Spencer (gage site SPWI4) on July 2. |
| May 2018 | Flood | Spencer | - | Flooding of the Little Sioux River continued from April, and was generally minor with impacts limited to near-river agricultural areas and the city park greenway in Spencer until falling below flood stage (gage site SPWI4) on May 8. However, rainfall was relentless over the first two weeks of May, totaling a widespread 3 to 5 inches in the upper Little Sioux Basin, including 5.01 inches at Lake Park, 4.85 inches 4 miles northwest of Milford, 4.69 inches in Spirit Lake, 3.95 inches near Everly and 3.20 inches at Spencer. The river rose back above flood stage on May 9 and crested again in minor flood stage (2.9 feet above flood stage) on May 13, inundating a large amount of pasture and crop land along the flood plain. The river dropped below flood stage on May 24. |
| September 2018 | Flood | Spencer | - | Rainfall throughout the Little Sioux Basin during the period of September 18-21 totaled generally 4 to 8 inches, resulting in major flooding. Sections of West Park Street, 1st Street and 2nd Street were flooded, and water encroached into several businesses in the south part of Spencer near WalMart along highways 71 and 18. Water also covered portions of county road B-40 southeast of Spencer. The Little Sioux River at Spencer (gage site SPWI4) crested at 6.6 feet above flood stage on September 21, and remained in minor flood state at the end of the month. |
| October 2018 | Flood | Spencer | - | Minor flooding of the city park and agricultural land near Spencer occurred as the Little Sioux River at Spencer (gage site SPWI4) crested 1.9 feet above flood stage on October 12. |
| June 2018 | Flood | Spencer | - | A week of prolific rainfall ending June 26 resulted in a widespread 5 to 9 inches of rainfall, much of which occurred on June 20 and 24. Specific weekly totals included 4.03 at Spencer, 6.70 near Everly, 7.87 at Lake Park, 8.60 3 miles south southeast of Lake Park and 10.65 4 miles northwest of Milford. Major flooding occurred with significant amounts of crop and pasture land inundated, as well as the city park in Spencer. Several roads in Spencer were under water including U.S. Highway 18/71 near the river and West Park, 1st and 2nd St., as well as Highway 18 between Dickens and Spencer as the river crested at Spencer (gage site SPWI4) at 7.4 feet above flood stage on June 26. The river remained in moderate flood stage at the end of the month. |
| June 2018 | Flash Flood | Spencer | - | One to two inches of rainfall in an hour caused significant street flooding in Spencer. |
| October 2018 | Flood | Spencer | - | A continuation of flooding from September, river levels on the Little Sioux River at Spencer (gage site SPWI4) continued to fall in early October. Impacts were limited to minor agricultural flooding. |
| May 2017 | Thunderstorm Wind | Spencer | - | Measured at the Spencer, IA airport. |
| June 2016 | Heavy Rain | Spencer | - | Rainfall of 1.63 inches was measured in 30 minutes. |
| June 2016 | Thunderstorm Wind | Spencer | - | Thunderstorm winds caused tree damage, including up to 4 inch diameter branches blown down. |
| June 2014 | Tornado (EF0) | Spencer | - | A brief tornado caused no reported damage. |
| June 2014 | Thunderstorm Wind | Spencer | - | Thunderstorm winds caused tree damage, including large limbs blown down. |
| May 2012 | Thunderstorm Wind | Spencer | - | A 71 mph gust was measured by RWIS equipment. |
| April 2012 | Tornado (EF0) | Spencer | - | A weak rope tornado caused no reported damage. |
| April 2012 | Hail | Spencer | - | Hail partially covered the ground. |
| June 2011 | Thunderstorm Wind | Spencer | - | Thunderstorm winds caused tree damage, including large branches and a few trees blown down. |
| April 2010 | Hail | Spencer | - | Hail was mostly pea size with a few stones up to dime size. |
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