4 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Calhoun County, Iowa. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flooding in Calhoun County is predominantly driven by standard river and creek flooding, complemented by a significant frequency of flash floods from heavy rainfall. Over the past 30 years, NOAA recorded 38 flood events and 23 flash flood events.
Heavy rainfall on saturated ground has repeatedly triggered local river and stream flooding, as occurred in December 2015 when one to three inches of rain caused county road closures. Severe flash flooding has also developed during saturated spring and summer conditions, such as in June 2018 and June 2019, when high atmospheric moisture and slow-moving weather systems produced excessive rainfall that soils could no longer absorb. Storm systems moving out of Nebraska have similarly brought heavy evening rainfall to the region, as observed in September 2016.
Homeowners, real estate agents, and journalists should pay the closest attention to properties located near rivers, streams, and low-lying county roads, as well as homes situated in mapped flood zones or lacking adequate elevation data.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
52 NOAA storm reports from Calhoun County describe what happened, in the words of the forecasters who covered it. Read the Iowa flood stories →
18 federal disaster declarations since 1979, 4 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | May 20, 2024 |
| Severe Storms, Straight-line Winds, And Tornadoes | Dec 15, 2021 |
| Severe Storms And Flooding | Mar 12, 2019 |
| Severe Storms, Flooding, And Tornadoes | Jun 1, 2010 |
| Severe Winter Storm | Jan 19, 2010 |
| Severe Winter Storms And Snowstorm | Dec 23, 2009 |
| Severe Storms And Flooding | Aug 17, 2007 |
| Severe Winter Storms | Feb 23, 2007 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
61 since 1996: 23 flash floods and 38 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 21, 2019 | — |
| Flash Flood | Jun 20, 2018 | $50,000 |
| Flash Flood | Sep 15, 2016 | $15,000 |
| Flood | Dec 14, 2015 | $20,000 |
| Flash Flood | Jun 27, 2010 | $25,000 |
| Flash Flood | Jun 27, 2010 | $50,000 |
| Flash Flood | Jul 22, 2010 | $250,000 |
| Flood | Jun 12, 2010 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 21, 2019. Periods of moderate to heavy rainfall are not uncommon throughout the spring and summer months, but given the very wet spring across Iowa, soils were primed and unable to hold copious amounts of new rainfall. The overall setup for this event was somewhat typical with a shortwave moving through the parent flow, and 850 mb low level jet aiding in convective initiation and moisture transport, precipitable water value…
Flash Flood · Jun 20, 2018. Without even looking at supporting variables, the setup for impactful weather could be gleaned from the general setup. A weak surface pressure system was slowly working its way across Iowa, situating its relevant boundaries primarily across southwest and southern Iowa. Within the warm sector, dew points were high in the low to mid 70s, especially considering afternoon air temperatures were only into the low 80s. E…
Flash Flood · Sep 15, 2016. Storms initiated out in the Nebraska Panhandle area the night prior, translating eastward through the night across northern Nebraska and southern South Dakota. As the storms approached and entered northern Iowa and southern Minnesota they strengthened, expanded in aerial coverage, and turned southward along the instability gradient. The primary results of the storms were gusty winds and heavy rainfall. The bulk…
Flood · Dec 14, 2015. Heavy rain that fell across the state in mid-December led to river flooding at many locations across central and southern Iowa. The ground was already saturated from a wet fall, with new rainfall of one to 3 inches fell across the area in a two-day span. The heavy rainfall also allowed for many area streams and creeks to reach bankfull or go into flood. County roads across several counties were closed due to flood…
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Calhoun County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.