30 flood insurance claims·$175,226 paid·9 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 Marshall 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 Marshall County is dominated by standard river and stream flooding alongside recurring flash floods from severe thunderstorms. According to NOAA Storm Events Database records from the last 30 years, the county experienced 67 flood events and 23 flash flood events.
Recent activity illustrates this risk. In May 2024, multiple rounds of slow-moving thunderstorms driven by a low-pressure system dropped 2 to 6 inches of rainfall across the region within 60-hour periods ending on May 21. These torrential downpours, accompanied by severe thunderstorms, tornadoes, and straight-line winds, triggered significant flash flooding over portions of northern and central Iowa through the morning of May 21.
National Flood Insurance Program claims data indicates that property owners across multiple zones have experienced flood impacts. Zone X recorded 13 claims with an average payout of $10,338 and an average recorded water depth of 5 inches, while Zone A saw 9 claims averaging $7,522 with an average water depth of 6 inches. Additional claims occurred in Zone UNKNOWN, Zone X_UNSHADED, and Zone X_SHADED. Consequently, homeowners, real estate agents, and journalists should pay the closest attention to properties located within designated flood zones as well as moderate-risk Zone X areas where historical claims and recorded standing water depths demonstrate tangible flood vulnerabilities.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
In flood insurance claims here that reported a flood depth, the average was 5 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2014, with 8 claims and $107,585 paid, the year of Severe Storms, Tornadoes, Straight-line Winds, and Flooding.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
77 NOAA storm reports from Marshall County describe what happened, in the words of the forecasters who covered it. Read the Iowa flood stories →
20 federal disaster declarations since 1965, 9 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | May 20, 2024 |
| Severe Storms | Aug 10, 2020 |
| Severe Storms And Flooding | Mar 12, 2019 |
| Severe Storm And Tornadoes | Jul 19, 2018 |
| Severe Storms, Tornadoes, And Flooding | May 19, 2013 |
| Severe Storms, Straight-line Winds, And Flooding | Jul 9, 2011 |
| Severe Storms, Tornadoes, And Flooding | May 25, 2008 |
| Severe Winter Storms | Feb 23, 2007 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
90 since 1996: 23 flash floods and 67 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flood | May 22, 2024 | — |
| Flood | May 21, 2024 | — |
| Flash Flood | Apr 22, 2022 | — |
| Flash Flood | Jun 15, 2019 | $50,000 |
| Flood | Mar 14, 2019 | $2.0M |
| Flood | Mar 14, 2019 | — |
| Flood | Mar 14, 2019 | $200,000 |
| Flood | Oct 9, 2018 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flood · May 22, 2024. There were several rounds of rainfall over the period starting around May 20 through around May 25. This is when there were two rounds of heavy rainfall along with severe thunderstorms including tornadoes and straight-line winds, detailed in respective severe entries for the month. 60-hour rainfall totals ending May 21 at 7pm were up to 4 to 6 inches over portions of Marshall, Tama, Poweshiek, and Jasper Counties.…
Flood · May 21, 2024. PLEASE NOTE, for tornadoes, please see separate Storm Data entry for May 21st. ||Multiple rounds of thunderstorms brought torrential rainfall, damaging winds, hail and destructive tornadoes to the state. These thunderstorms were the result of a low pressure system which lifted north into the area on the night of May 20th, 2024, producing slow moving storms that dropped 2 to 4 inches of rainfall. This resulted in f…
Flash Flood · Apr 22, 2022. A warm front moved across the area late on the evening of April 21 into April 22. While thunderstorms remained below severe criteria, deep saturation and precipitable water values over 1.5 inches allowed for a band of heavier precipitation to set up over a narrow corridor in central Iowa. Several locations received over 3 inches of rain and a few areas saw flash flooding within towns, resulting in brief road closu…
Flash Flood · Jun 15, 2019. Increasingly humid conditions, a weak low pressure system, and an impinging northern weak cold front combined to create an environment ripe for strong to severe storms across northern and central Iowa, with much of the severe activity through central Iowa. ||The resulting environment from the aforementioned ingredients included SBCAPE values in the 2000-3000+ J/kg range, marginal effective bulk shear around 30 kts…
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 Marshall 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.