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Iowa hail risk

99 counties scored 0 rated Very High

Polk County has the highest hail risk in Iowa, scoring 97.9 out of 100 — rated "Relatively High" by FEMA's National Risk Index. NOAA has recorded 3,386 hail events across Iowa over the past decade.

# County NRI score Rating NOAA events
2016–2026
1 Polk County 97.9 Relatively High 162
2 Linn County 97.6 Relatively High 114
3 Hardin County 97.2 Relatively High 21
4 Carroll County 96.9 Relatively High 15
5 Scott County 96.1 Relatively High 106
6 Pottawattamie County 95.7 Relatively High 68
7 Sioux County 95.5 Relatively High 49
8 Johnson County 95.3 Relatively High 86
9 Woodbury County 95 Relatively High 51
10 Plymouth County 93.5 Relatively Moderate 62
11 Calhoun County 92.8 Relatively Moderate 22
12 Buena Vista County 91.9 Relatively Moderate 22
13 Muscatine County 91.7 Relatively Moderate 44
14 Webster County 91.2 Relatively Moderate 51
15 Sac County 90.9 Relatively Moderate 17
16 Des Moines County 90.1 Relatively Moderate 28
17 Lyon County 89.4 Relatively Moderate 32
18 Dubuque County 89.3 Relatively Moderate 48
19 Cherokee County 88.6 Relatively Moderate 32
20 Black Hawk County 87.3 Relatively Moderate 59
21 Clinton County 87 Relatively Moderate 43
22 Story County 86.8 Relatively Moderate 126
23 Delaware County 86.4 Relatively Moderate 9
24 Harrison County 86.4 Relatively Moderate 28
25 Osceola County 86.3 Relatively Moderate 24
26 Lee County 85.7 Relatively Moderate 44
27 Washington County 83.3 Relatively Moderate 29
28 Winneshiek County 83.1 Relatively Moderate 11
29 Clay County 83 Relatively Moderate 45
30 Adair County 82.6 Relatively Moderate 49
31 Monona County 82.6 Relatively Moderate 22
32 Jackson County 82.5 Relatively Moderate 13
33 Clayton County 82.4 Relatively Moderate 32
34 O'Brien County 82.2 Relatively Moderate 46
35 Fayette County 82.1 Relatively Moderate 24
36 Dallas County 81.6 Relatively Moderate 48
37 Floyd County 80.9 Relatively Moderate 37
38 Marshall County 80.9 Relatively Moderate 33
39 Ida County 80.7 Relatively Moderate 35
40 Henry County 80 Relatively Moderate 33
41 Chickasaw County 79.8 Relatively Moderate 19
42 Allamakee County 79.7 Relatively Moderate 3
43 Cass County 79.5 Relatively Moderate 12
44 Jasper County 79.1 Relatively Moderate 55
45 Shelby County 78.5 Relatively Moderate 18
46 Palo Alto County 77.7 Relatively Moderate 26
47 Crawford County 76.8 Relatively Moderate 19
48 Cerro Gordo County 76.1 Relatively Moderate 58
49 Page County 76 Relatively Moderate 27
50 Benton County 75.3 Relatively Moderate 60
51 Jefferson County 75.3 Relatively Moderate 12
52 Poweshiek County 74.3 Relatively Moderate 17
53 Union County 74.2 Relatively Moderate 30
54 Buchanan County 74 Relatively Moderate 32
55 Iowa County 73.5 Relatively Moderate 28
56 Jones County 73 Relatively Low 23
57 Mills County 72.7 Relatively Low 38
58 Hamilton County 72.3 Relatively Low 17
59 Montgomery County 72.1 Relatively Low 31
60 Wright County 72 Relatively Low 13
61 Grundy County 70.3 Relatively Low 15
62 Bremer County 69.2 Relatively Low 22
63 Dickinson County 68.9 Relatively Low 57
64 Cedar County 68.4 Relatively Low 42
65 Fremont County 68.2 Relatively Low 35
66 Keokuk County 68.2 Relatively Low 19
67 Madison County 68 Relatively Low 25
68 Louisa County 67.9 Relatively Low 18
69 Audubon County 66.4 Relatively Low 12
70 Boone County 66 Relatively Low 41
71 Mahaska County 64.6 Relatively Low 10
72 Lucas County 64.2 Relatively Low 16
73 Tama County 63.9 Relatively Low 24
74 Hancock County 63.5 Relatively Low 38
75 Humboldt County 63.2 Relatively Low 27
76 Greene County 63.1 Relatively Low 20
77 Pocahontas County 63.1 Relatively Low 34
78 Wapello County 62.9 Relatively Low 18
79 Ringgold County 62.5 Relatively Low 11
80 Taylor County 62.5 Relatively Low 28
81 Winnebago County 61.6 Relatively Low 18
82 Guthrie County 59.9 Relatively Low 24
83 Howard County 59.8 Relatively Low 10
84 Appanoose County 58.3 Relatively Low 35
85 Davis County 57.6 Relatively Low 11
86 Emmet County 57.5 Relatively Low 15
87 Mitchell County 57.1 Relatively Low 17
88 Butler County 55.4 Relatively Low 40
89 Van Buren County 55.1 Relatively Low 54
90 Franklin County 53.7 Relatively Low 35
91 Marion County 53.5 Relatively Low 64
92 Kossuth County 51.7 Relatively Low 36
93 Wayne County 51.5 Relatively Low 12
94 Adams County 50.3 Relatively Low 19
95 Warren County 49.2 Relatively Low 91
96 Decatur County 47.6 Relatively Low 10
97 Clarke County 45.3 Relatively Low 55
98 Monroe County 30.3 Very Low 16
99 Worth County 29.6 Very Low 14

Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.

Hail risk nationally:

Top 50 US counties

Other hazard risks in Iowa:

WildfireInland FloodingCoastal FloodingEarthquakeHeat WaveTornadoHurricaneStrong WindWinter WeatherIce StormCold WaveLightningDroughtLandslideAvalancheTsunamiVolcanic Activity

Frequently asked questions

What is the highest hail risk county in Iowa?

Polk County, IA has the highest hail risk in Iowa, with a FEMA National Risk Index score of 97.9 out of 100 (rated "Relatively High").

What causes hail risk in Iowa?

Hail risk reflects expected annual losses from damaging hailstones to structures, vehicles, and crops. High scores cluster in the central plains and Front Range — a corridor sometimes called "Hail Alley" — where large-diameter hail is most frequent. Hail causes over $10 billion in US property damage in active years, much of it to roofs, vehicles, and crops.