Monona storm history
Storm events recorded in Monona, Iowa between 1950 and 2025.
505
Total events
30
Tornadoes
142
Hail
23
Floods
5
Deaths
$265.5M
Property damage
Most significant events
Strongest tornadoes, deadliest events, and biggest damage in this county. Up to 50 shown.
A tornado caused extensive damage in the Mapleton area with about 100 houses destroyed and many others severely damaged in a 12 to 15 block area on the southwest side of town. This caused the displacement of around 500 to 600 people. Most garages and stand alone structures were d…
This tornado tragically hit a boyscout camp north of Little Sioux Iowa killing 4 young scouts. The tornado initially touched down in Burt county Nebraska, crossed into Harrison county Iowa near mile marker 97 on Interstate 29, and then finally crossed into Monona county Iowa abou…
Widespread dense fog reduced visibility to near 0 across Monona County. The Iowa State Patrol reported fog was present at a two-vehicle accident near the intersection of 130th Street and Walnut Avenue east of Mapleton at approximately 7:41 PM CST on December 25th. An eastbound ve…
This is for flooding along the Maple River. The river gage at Mapleton, operated by the USGS, peaked at 23.60 feet at 6:15 pm on March 14th. Minor flood stage is 21 feet, moderate flood stage is 24 feet . Preliminarily this peak is the 2nd highest on record. Ice jamming may have …
Flooding along the Missouri River gradually worsened over Monona county during June and July as record releases from Gavins Point Dam brought widespread flooding along the river. Conditions improved markedly during August as releases were reduced and the river level at Decatur dr…
Rainfall of 3 to 4 inches produce flash flooding of streets in Onawa. Other creeks across the county flooded county roads causing road, bridge and levee damage.
High Wind High Wind
No observations within the county. Estimated maximum wind gusts of 58-63 mph based on surrounding observations.
High Wind High Wind
Personal weather station measured wind gust of 64 mph near Rodney, IA and 60 mph measured near Dunlap, IA.
Winter Storm Winter Storm
The office received snowfall reports of 4.5 to 6.2 inches from the public and CO-OP Observers. The heaviest snowfall was estimated around the eastern edge of the county.
High Wind High Wind
No observations within the county. Estimated maximum wind gusts of 55-60 mph based on surrounding observations.
Thunderstorm Wind Thunderstorm Wind
Law enforcement report of trees blown down. Winds gusted to an estimated 90 mph.
Thunderstorm Wind Thunderstorm Wind
Personal weather station measured wind gust of 73 mph.
Excessive Heat Excessive Heat
Personal weather station measured heat index of 112, 116 and 117 degrees.
Excessive Heat Excessive Heat
Personal weather station measured heat index of 109 and 110 degrees.
Blizzard Blizzard
Interstate 29 closed from Missouri Valley to South Dakota border due to blizzard conditions and powerlines across the road at mile marker 110. Generally 6 to 9 of snow with wind gusts estimated at 50 to 70 mph.
High Wind High Wind
No observations within the county. Estimated wind gusts of 50-70 mph with a 73 mph measured wind gust LSR just south of the Monona/Harrison county line.
Thunderstorm Wind Thunderstorm Wind
Public estimated wind gusts of 60 to 70 mph, lasting nearly 10 minutes.
Blizzard Blizzard
General snowfall amounts of 2 to 3 inches. While there is no ASOS/AWOS in the county, surrounding conditions supporting blizzard criteria. Wind gusts up to 55 mph.
High Wind High Wind
Personal weather station measured 55 mph wind gust. Surrounding conditions support High Wind Warning.
Extreme Cold/Wind Chill Extreme Cold/Wind Chill
Wind chill got as low as -30 in the county.
Extreme Cold/Wind Chill Extreme Cold/Wind Chill
Wind chill got as low as -33 in the county.
High Wind High Wind
Though no direct measurements were made in the county of severe level wind gusts, observations from surrounding counties support the high likelihood of wind gusts up to 58 mph occurring the afternoon of the 19th.
Excessive Heat Excessive Heat
Max afternoon heat indices ranging from 118 to 123 degrees were reported from mesonet stations across the county.
Thunderstorm Wind Thunderstorm Wind
A Department of Highways station measured a 61 miles per hour wind gust.
Funnel Cloud Funnel Cloud
The office received a delayed report of a rope funnel cloud from the public.
Funnel Cloud Funnel Cloud
The office received multiple photos of a funnel cloud via social media.
Flash Flood Flash Flood
At 04:56 am CDT on the 25th, law enforcement reported that a levee on the Little Sioux River failed 600 yards south of Highway 141 resulting in flash flooding in the surrounding areas. Since this event was tied to the river flooding at the end of this month, the damage estimates …
Flood Flood
River flooding from upstream excessive rain impacted the region, bringing the Missouri River to moderate flood stage. The Missouri River crested at 37.55 feet at the Decatur gauge at 03:45 CDT on 6/26. Flood stage at this gauge is 35.0 feet. Additional flooding for the same reaso…
Hail Hail
Golf ball sized hail was reported by a trained spotter along Interstate 29 west of Whiting.
Hail Hail
The office received a photo of significant damage to siding and windows on a home in Whiting, Iowa. This was accompanied by significant car damage and tree damage in the surrounding area. Hail was estimated to have ranged from golf ball to baseball sized.
Hail Hail
A report from mPING of 3.5 inch hail.
Thunderstorm Wind Thunderstorm Wind
An 83 miles per hour wind gust was recorded on a personal weather station.
Hail Hail
The public reported quarter sized hail on the west side of Blencoe via mPING.
Tornado EF0 Tornado
This is a continuation of the EF-1 tornado that touched down in Harrison County to the north-northwest of Magnolia, IA. The tornado was already weakening as it entered Monona County, only producing low-end EF-0 damage to trees as it crossed the county line. The tornado dissipated…
Tornado EF0 Tornado
A short-lived tornado developed in an agricultural field and moved generally northeast across fields and pastureland, damaging outbuildings of farmsteads near the intersection of 280th and Poplar Roads. The tornado appeared to dissipate in pastureland before reaching State Highwa…
Tornado EF1 Tornado
A tornado developed near the intersection of 260th and 270th Streets. It produced damage to outbuildings at a farmstead near this intersection and tossed some fiberglass boats. The tornado moved across agricultural fields generally northeast paralleling State Highway 183 to the w…
Winter Storm Winter Storm
Snow began to fall across the county just before noon on the 18th. By 7:00 pm that evening, strong gusty winds up to 40 miles per hour had blown roads across the county closed due to significant blowing and drifting snow. An estimated 2 to 4 inches of snow fell across the county,…
Extreme Cold/Wind Chill Extreme Cold/Wind Chill
Wind chills across the county dropped under 35 degrees below zero every night during the duration of this event. The coldest wind chills were felt on January 13th and 14th. The coldest recorded wind chill in the county was minus 44 degrees measured in Sloan on the evening of the …
Winter Storm Winter Storm
An estimated 6 to 7 inches of snow fell across the county during this winter storm. This includes a 6 inch snow report out of Mapleton. Strong winds gusting 40 to 50 miles per hour were also measured across the county. This included an observed wind gust of 46 miles per hour in S…
Winter Storm Winter Storm
An estimated 5 to 10 inches of snow fell across the county for this winter storm. The highest snowfall totals were in the western part of the county near the Missouri River. This includes a public report of 6 inches of snow in Little Sioux, and another public report of 10 inches …
Excessive Heat Excessive Heat
For 4 days beginning on August 21, the high temperature in Mapleton reached at least 95. The highest observed temperature was 99, occurring on both August 22 and August 23. Dew point temperatures in the area were in the mid to upper 70s which yielded a heat index of at least 105 …
Thunderstorm Wind Thunderstorm Wind
A personal weather station measured a peak wind gust of 59 mph.
Hail Hail
Monona County dispatch relayed a report from an officer in Mapleton of pea to quarter size hail.
Hail Hail
Public reported 1-inch hail via mPING.
Hail Hail
Broadcast media relayed reported of 1.5-inch hail.
Hail Hail
Trained spotter reported quarter sized hail cover the ground in Ute.
Winter Weather Winter Weather
Public reported 3-inches of snowfall.
Winter Storm Winter Storm
COOP Observer in Little Sioux reported 7-inches of snow and a glaze of ice.
Events by year
| Year | Events | Tornadoes |
|---|---|---|
| 2025 | 16 | 0 |
| 2024 | 19 | 3 |
| 2023 | 8 | 0 |
| 2022 | 5 | 0 |
| 2021 | 4 | 0 |
| 2020 | 4 | 0 |
| 2019 | 10 | 0 |
| 2018 | 4 | 0 |
| 2017 | 4 | 0 |
| 2016 | 11 | 0 |
| 2015 | 5 | 0 |
| 2014 | 14 | 0 |
| 2013 | 17 | 1 |
| 2012 | 22 | 1 |
| 2011 | 29 | 2 |
| 2010 | 18 | 0 |
| 2009 | 8 | 0 |
| 2008 | 17 | 3 |
| 2007 | 32 | 0 |
| 2006 | 11 | 0 |
| 2005 | 7 | 0 |
| 2004 | 12 | 0 |
| 2003 | 19 | 0 |
| 2002 | 11 | 0 |
| 2001 | 23 | 3 |
| 2000 | 10 | 0 |
| 1999 | 12 | 1 |
| 1998 | 25 | 4 |
| 1997 | 12 | 0 |
| 1996 | 22 | 0 |
| 1995 | 2 | 0 |
| 1994 | 18 | 0 |
| 1993 | 1 | 0 |
| 1992 | 5 | 1 |
| 1991 | 2 | 1 |
| 1990 | 4 | 0 |
| 1989 | 2 | 0 |
| 1988 | 1 | 0 |
| 1987 | 5 | 1 |
| 1986 | 4 | 1 |
| 1985 | 2 | 0 |
| 1984 | 4 | 0 |
| 1983 | 1 | 0 |
| 1981 | 6 | 0 |
| 1980 | 5 | 0 |
| 1979 | 1 | 0 |
| 1978 | 1 | 0 |
| 1977 | 2 | 1 |
| 1976 | 1 | 0 |
| 1975 | 3 | 0 |
| 1974 | 5 | 0 |
| 1970 | 3 | 0 |
| 1969 | 1 | 0 |
| 1968 | 3 | 2 |
| 1967 | 2 | 1 |
| 1966 | 1 | 0 |
| 1965 | 2 | 2 |
| 1963 | 3 | 0 |
| 1962 | 2 | 1 |
| 1958 | 1 | 0 |
| 1953 | 1 | 1 |