FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Iowa Disaster Risk

Natural disaster risk data for all 99 counties.

Avg FEMA Rating

Very Low

Avg Percentile

40th

Counties with Data

of 99 total

County risk atlas

Iowa hazard exposure by county

A compact 2.5D surface of FEMA National Risk Index percentiles. Toggle composite, flood, wildfire, hurricane, tornado, and earthquake risk to see which counties carry the highest relative exposure without loading the full national explorer dataset.

Counties

99/99

Avg composite

40th

Risk layers

Highest Risk Counties

Polk County

Relatively Moderate

92th percentile

Johnson County

Relatively Moderate

87th percentile

Linn County

Relatively Moderate

87th percentile

Scott County

Relatively Moderate

85th percentile

Woodbury County

Relatively Moderate

83th percentile

Lowest Risk Counties

Worth County

Very Low

10th percentile

Monroe County

Very Low

10th percentile

Grundy County

Very Low

13th percentile

Ringgold County

Very Low

14th percentile

Osceola County

Very Low

15th percentile

All Iowa Counties

County	Percentile	FEMA Rating	Flood	Wildfire	Tornado	Earthquake
Polk County	92th	Relatively Moderate	92.1	57.7	98.1	66.8
Johnson County	87th	Relatively Moderate	79.8	64.4	98.2	45.1
Linn County	87th	Relatively Moderate	86.7	47.0	95.5	57.2
Scott County	85th	Relatively Moderate	88.4	52.2	82.9	75.1
Woodbury County	83th	Relatively Moderate	78.2	87.4	96.5	30.8
Pottawattamie County	80th	Relatively Low	74.6	67.2	95.2	26.9
Black Hawk County	77th	Relatively Low	76.6	36.9	91.4	39.1
Cerro Gordo County	70th	Relatively Low	69.0	26.7	89.3	24.2
Story County	69th	Relatively Low	69.1	30.3	91.3	34.8
Wapello County	65th	Relatively Low	69.3	61.6	81.8	37.3
Clinton County	65th	Relatively Low	66.9	50.1	79.0	45.4
Dubuque County	64th	Relatively Low	65.4	22.8	84.0	31.1
Lee County	63th	Relatively Low	70.4	48.7	70.3	55.5
Marshall County	62th	Relatively Low	63.1	62.1	82.7	27.5
Crawford County	61th	Relatively Low	56.1	46.2	82.4	9.9
Dallas County	61th	Relatively Low	60.4	40.6	84.7	25.6
Cass County	60th	Relatively Low	43.4	40.6	75.8	16.2
Webster County	60th	Relatively Low	47.1	19.1	92.1	20.6
Hardin County	58th	Relatively Low	52.9	39.0	72.2	19.7
Muscatine County	58th	Relatively Low	62.6	60.9	55.0	54.1
Carroll County	58th	Relatively Low	37.5	28.5	85.5	19.8
Des Moines County	56th	Relatively Low	56.0	42.9	69.4	56.7
Sioux County	52th	Relatively Low	49.5	39.7	79.4	19.1
Fayette County	51th	Relatively Low	59.2	14.5	71.5	19.1
Davis County	50th	Relatively Low	32.7	68.6	68.7	33.3
Delaware County	50th	Relatively Low	61.7	12.4	58.5	24.6
Union County	50th	Relatively Low	30.1	49.8	57.1	24.2
Adair County	49th	Relatively Low	23.8	34.1	62.4	12.3
Plymouth County	49th	Relatively Low	45.2	70.5	77.4	14.4
Floyd County	48th	Relatively Low	56.3	28.8	68.0	11.0
Tama County	45th	Relatively Low	42.4	65.5	57.4	21.7
Calhoun County	45th	Relatively Low	20.6	8.5	73.6	14.6
Washington County	44th	Relatively Low	48.4	54.9	57.0	35.6
Jasper County	44th	Relatively Low	40.2	53.1	70.3	28.5
Hamilton County	43th	Relatively Low	41.0	13.5	64.8	17.1
Emmet County	43th	Very Low	20.4	23.8	43.2	5.2
Clayton County	42th	Very Low	58.0	12.3	54.0	14.5
Wright County	42th	Very Low	35.1	7.3	54.4	16.8
Appanoose County	41th	Very Low	30.0	59.5	73.1	31.5
Page County	40th	Very Low	27.5	34.6	69.6	20.7
Buena Vista County	39th	Very Low	32.9	17.9	74.0	19.4
Audubon County	39th	Very Low	19.8	33.4	59.7	6.7
Taylor County	38th	Very Low	20.9	36.5	54.3	18.5
Allamakee County	38th	Very Low	50.5	16.7	55.7	12.0
Mitchell County	38th	Very Low	36.2	11.7	47.7	4.7
Clay County	36th	Very Low	53.8	29.6	53.8	14.2
Dickinson County	36th	Very Low	49.9	54.2	64.0	13.4
Winneshiek County	36th	Very Low	47.5	22.5	60.8	10.6
Warren County	36th	Very Low	35.9	59.4	65.9	20.5
Jackson County	36th	Very Low	43.3	35.7	54.8	26.4
Madison County	36th	Very Low	36.6	59.9	54.9	17.9
Marion County	34th	Very Low	41.2	50.6	67.7	30.9
Cherokee County	34th	Very Low	39.1	24.5	60.8	10.7
Montgomery County	34th	Very Low	34.6	35.0	61.6	16.0
Van Buren County	34th	Very Low	40.8	52.2	54.7	31.2
Pocahontas County	33th	Very Low	18.1	4.2	49.7	11.8
Jones County	33th	Very Low	46.4	27.4	51.0	21.5
Kossuth County	32th	Very Low	26.7	13.3	61.1	11.5
Greene County	32th	Very Low	12.0	10.3	65.5	11.1
Chickasaw County	32th	Very Low	39.6	19.6	59.3	12.0
Harrison County	31th	Very Low	37.0	59.8	60.1	11.8
Poweshiek County	31th	Very Low	20.3	46.1	59.8	25.6
Henry County	31th	Very Low	26.7	47.9	48.5	43.6
Winnebago County	31th	Very Low	25.6	13.6	45.8	10.8
Mahaska County	30th	Very Low	36.4	42.4	54.6	29.5
Lucas County	30th	Very Low	22.7	54.6	57.3	24.1
Benton County	29th	Very Low	40.3	36.4	43.6	20.5
Hancock County	29th	Very Low	21.6	6.6	50.5	11.4
Boone County	28th	Very Low	28.8	15.9	57.2	16.6
Iowa County	28th	Very Low	32.6	61.1	59.9	26.2
Sac County	27th	Very Low	17.2	9.8	60.0	10.1
Butler County	27th	Very Low	37.2	22.4	48.3	9.2
Jefferson County	27th	Very Low	20.4	54.7	54.1	38.1
Guthrie County	27th	Very Low	22.0	39.1	64.1	9.3
Monona County	25th	Very Low	25.0	63.5	58.0	14.0
Bremer County	25th	Very Low	33.4	22.9	52.3	14.3
Humboldt County	24th	Very Low	18.9	5.1	45.5	8.6
Buchanan County	24th	Very Low	38.6	7.2	37.5	16.7
Decatur County	24th	Very Low	15.8	52.1	48.3	18.6
Shelby County	23th	Very Low	19.5	21.1	63.2	7.7
Wayne County	22th	Very Low	14.0	43.2	55.2	20.3
Franklin County	22th	Very Low	14.0	6.1	50.3	7.5
Keokuk County	22th	Very Low	29.6	44.4	42.3	21.9
Cedar County	22th	Very Low	27.6	31.8	45.6	27.4
Adams County	20th	Very Low	11.5	31.7	38.0	8.2
Lyon County	19th	Very Low	19.6	28.4	45.9	7.5
Mills County	18th	Very Low	27.4	52.4	55.9	8.9
Clarke County	18th	Very Low	9.6	42.0	44.6	14.9
Ida County	18th	Very Low	18.4	20.2	59.1	5.8
Louisa County	17th	Very Low	20.9	35.2	34.2	30.2
O'Brien County	16th	Very Low	18.5	12.7	48.7	9.8
Howard County	16th	Very Low	25.4	9.3	40.6	6.8
Palo Alto County	15th	Very Low	9.0	11.0	38.8	6.2
Fremont County	15th	Very Low	18.4	36.8	45.7	13.3
Osceola County	15th	Very Low	14.9	12.9	42.7	9.3
Ringgold County	14th	Very Low	5.0	32.5	31.5	8.6
Grundy County	13th	Very Low	14.2	8.0	34.8	10.1
Monroe County	10th	Very Low	9.1	40.0	39.9	14.5
Worth County	10th	Very Low	10.7	3.2	36.0	4.8

Frequently Asked Questions

Which county in Iowa has the highest natural disaster risk?

Polk County has the highest natural disaster risk in Iowa, rated Relatively Moderate (92th percentile nationally), based on FEMA National Risk Index data.

Which county in Iowa is the safest from natural disasters?

Worth County has the lowest natural disaster risk in Iowa, rated Very Low (10th percentile nationally), based on FEMA NRI data.

What natural disasters are most common in Iowa?

Iowa counties face varying levels of risk from floods, wildfires, tornadoes, earthquakes, and hurricanes. The FEMA National Risk Index scores each county across 18 hazard types. See individual county pages for detailed hazard breakdowns.

How is natural disaster risk measured by county?

The FEMA National Risk Index (NRI) measures natural disaster risk using expected annual loss, social vulnerability, and community resilience. Scores are normalized nationally, with ratings from Very Low to Very High across 18 natural hazard types.

Prepare your household for natural disasters

FEMA's Ready.gov provides county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.

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