286 flood insurance claims·$13.0M paid·6 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 Story 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.
Slow-moving thunderstorms and heavy rainfall causing both general flooding and flash flooding dominate the flood profile of Story County, Iowa. Over the last 30 years, the NOAA Storm Events Database recorded 78 flood events and 64 flash flood events. Recent instances include May 2024, when multiple rounds of thunderstorms dropped 2 to 4 inches of rainfall and caused flash flooding across portions of central Iowa, and June 2022, when rainfall totals of 4 inches or greater pushed the South Skunk River in Ames at US 30 briefly into flood stage.
National Flood Insurance Program records indicate claims across multiple zones, with Zone A experiencing the highest frequency at 189 claims, averaging $56,113 per payout with an average recorded water depth of 8 inches. Zone X recorded 35 claims with an average payout of $12,592 and an average water depth of 3 inches, while Shaded Zone X logged 28 claims averaging $28,819 with an average water depth of 7 inches. Unshaded Zone X recorded 23 claims with an average payout of $134,239 and an average water depth of 6 inches, and unknown zones logged 11 claims averaging $31,893 with an average water depth of 13 inches.
Homeowners, real estate agents, and journalists should pay the closest attention to properties located within Zone A and shaded or unshaded Zone X areas, where historical claims demonstrate both recurring water accumulation and significant financial payout averages.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
21% of Story County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
240 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 7 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 2010, with 78 claims and $8.2M paid, the year of Severe Winter Storm and Severe Storms, Flooding, and Tornadoes.
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.
130 NOAA storm reports from Story County describe what happened, in the words of the forecasters who covered it. Read the Iowa flood stories →
21 federal disaster declarations since 1969, 6 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | May 20, 2024 |
| Severe Storms | Aug 10, 2020 |
| Severe Storms, Tornadoes, Straight-line Winds, And Flooding | Jun 6, 2018 |
| Severe Storms, Tornadoes, And Flooding | May 19, 2013 |
| Severe Storms, Straight-line Winds, And Flooding | Jul 9, 2011 |
| Severe Storms, Flooding, And Tornadoes | Jun 1, 2010 |
| Severe Winter Storm | Jan 19, 2010 |
| Severe Storms, Tornadoes, And Flooding | May 25, 2008 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
142 since 1996: 64 flash floods and 78 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flood | May 21, 2024 | — |
| Flash Flood | Apr 22, 2022 | — |
| Flood | Jun 15, 2022 | — |
| Flash Flood | Jul 14, 2021 | — |
| Flood | May 24, 2019 | — |
| Flood | May 24, 2019 | $5,000 |
| Flood | May 24, 2019 | $10,000 |
| Flood | May 23, 2019 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
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…
Flood · Jun 15, 2022. Storms from the 14th into the 15th resulted in severe weather and heavy rainfall. A number of stations and reports of 4 inches or greater rainfall were received in and around Story County. As a result, the South Skunk River in Ames at US 30 briefly went into flood stage on the 15th of June.
Flash Flood · Jul 14, 2021. A surface low pressure system was centered over Kansas and Nebraska with attendant warm front draped across north central Iowa. This was bisected by an outflow boundary from morning convection across western Iowa. As morning activity exited the are the atmosphere quickly recovered steep low and mid level lapse rates exceeded 8 C/km with 0-6 km shear over 40 knots. Near the remnant outflow boundary 0-1 km SRH excee…
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 Story 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.