Lightning Risk in Iowa

All Iowa counties ranked by FEMA National Risk Index lightning score

Lightning risk — electrical discharges from storms that ignite fires and cause casualties — is rated for 99 of 99 Iowa counties in FEMA's National Risk Index. Linn County carries the state's highest lightning score at 85.1, with $1M in expected annual lightning losses.

2 Iowa counties are rated High or Very High for lightning, and expected annual losses from lightning total roughly $17M statewide. The full ranking below links to each county's complete 18-hazard risk profile.

County Rankings — Lightning

#CountyLightning ScoreRatingAnn. Freq.Ann. Loss
1 Linn County
85.1
High 42.84 / yr $1M
2 Scott County
83.5
High 42.78 / yr $1M
3 Van Buren County
81.3
Medium 44.97 / yr $593K
4 Polk County
78.1
Medium 44.35 / yr $816K
5 Johnson County
74.5
Medium 44.31 / yr $830K
6 Pottawattamie County
72.6
Medium 45.64 / yr $625K
7 Muscatine County
72.2
Medium 44.63 / yr $553K
8 Jefferson County
67.6
Medium 44.91 / yr $380K
9 Des Moines County
66.4
Medium 45.22 / yr $454K
10 Henry County
63.5
Medium 45.03 / yr $368K
11 Lee County
61.8
Medium 45.81 / yr $350K
12 Warren County
60.5
Medium 45.36 / yr $560K
13 Palo Alto County
59.2
Medium 40.80 / yr $512K
14 Davis County
57.8
Medium 45.02 / yr $213K
15 Story County
56.5
Low 42.95 / yr $380K
16 Black Hawk County
54.8
Low 41.59 / yr $319K
17 Wapello County
52.5
Low 45.18 / yr $249K
18 Clinton County
52.0
Low 42.15 / yr $261K
19 Woodbury County
51.7
Low 41.90 / yr $250K
20 Dallas County
51.0
Low 44.48 / yr $444K
21 Washington County
48.6
Low 44.40 / yr $220K
22 Appanoose County
46.3
Low 45.65 / yr $164K
23 Emmet County
38.6
Low 39.40 / yr $159K
24 Plymouth County
37.2
Low 40.11 / yr $162K
25 Mahaska County
35.0
Low 44.99 / yr $152K
26 Dubuque County
34.9
Low 39.75 / yr $236K
27 Kossuth County
34.4
Low 41.14 / yr $194K
28 Marion County
34.3
Low 44.58 / yr $166K
29 Jasper County
31.5
Low 43.64 / yr $133K
30 Page County
30.5
Low 46.26 / yr $107K
31 Webster County
30.4
Low 43.25 / yr $127K
32 Louisa County
30.1
Low 45.37 / yr $138K
33 Sioux County
29.9
Low 39.38 / yr $187K
34 Delaware County
28.1
Low 40.48 / yr $107K
35 Madison County
28.1
Low 44.71 / yr $92K
36 Keokuk County
28.0
Low 44.63 / yr $117K
37 Crawford County
26.9
Low 43.53 / yr $104K
38 Ida County
26.9
Low 41.99 / yr $102K
39 Marshall County
26.3
Low 43.05 / yr $93K
40 Cherokee County
26.0
Low 40.84 / yr $91K
41 Pocahontas County
24.0
Low 42.08 / yr $89K
42 Wright County
23.8
Very Low 41.66 / yr $83K
43 Carroll County
21.9
Very Low 43.62 / yr $87K
44 Fayette County
21.7
Very Low 39.43 / yr $67K
45 Winnebago County
21.6
Very Low 40.41 / yr $71K
46 Howard County
21.4
Very Low 38.26 / yr $110K
47 Cerro Gordo County
21.0
Very Low 41.13 / yr $70K
48 Cedar County
20.4
Very Low 43.21 / yr $114K
49 Calhoun County
20.2
Very Low 42.92 / yr $65K
50 Winneshiek County
20.0
Very Low 38.05 / yr $91K
51 Poweshiek County
20.0
Very Low 44.37 / yr $79K
52 Union County
19.4
Very Low 45.13 / yr $52K
53 Buena Vista County
19.2
Very Low 41.52 / yr $65K
54 Allamakee County
19.1
Very Low 38.06 / yr $57K
55 Taylor County
19.0
Very Low 45.62 / yr $53K
56 Clayton County
18.8
Very Low 38.98 / yr $70K
57 O'Brien County
18.6
Very Low 39.76 / yr $112K
58 Cass County
17.6
Very Low 44.84 / yr $47K
59 Hamilton County
17.5
Very Low 42.39 / yr $69K
60 Iowa County
17.1
Very Low 44.73 / yr $70K
61 Hancock County
17.0
Very Low 41.66 / yr $69K
62 Decatur County
16.8
Very Low 45.63 / yr $55K
63 Jackson County
16.5
Very Low 41.16 / yr $70K
64 Harrison County
16.4
Very Low 44.16 / yr $55K
65 Floyd County
15.9
Very Low 40.64 / yr $52K
66 Jones County
15.7
Very Low 41.82 / yr $82K
67 Monroe County
15.5
Very Low 45.53 / yr $75K
68 Lucas County
15.1
Very Low 45.10 / yr $42K
69 Benton County
15.0
Very Low 44.07 / yr $85K
70 Buchanan County
14.9
Very Low 40.91 / yr $81K
71 Osceola County
14.7
Very Low 38.81 / yr $46K
72 Chickasaw County
14.2
Very Low 39.81 / yr $52K
73 Dickinson County
13.8
Very Low 38.54 / yr $60K
74 Sac County
13.7
Very Low 42.78 / yr $77K
75 Mills County
13.7
Very Low 46.61 / yr $73K
76 Montgomery County
13.3
Very Low 45.53 / yr $48K
77 Boone County
13.2
Very Low 43.71 / yr $82K
78 Humboldt County
12.9
Very Low 42.12 / yr $53K
79 Monona County
11.8
Very Low 43.48 / yr $41K
80 Tama County
11.5
Very Low 43.60 / yr $34K
81 Clay County
11.4
Very Low 39.75 / yr $57K
82 Fremont County
11.4
Very Low 47.21 / yr $43K
83 Wayne County
11.2
Very Low 45.94 / yr $29K
84 Mitchell County
10.8
Very Low 39.69 / yr $44K
85 Adair County
10.2
Very Low 45.35 / yr $30K
86 Hardin County
9.8
Very Low 41.62 / yr $33K
87 Clarke County
9.6
Very Low 45.00 / yr $46K
88 Lyon County
9.2
Very Low 38.95 / yr $47K
89 Greene County
9.1
Very Low 44.06 / yr $35K
90 Shelby County
8.9
Very Low 44.14 / yr $46K
91 Bremer County
8.1
Very Low 40.55 / yr $48K
92 Audubon County
7.3
Very Low 44.44 / yr $22K
93 Guthrie County
7.3
Very Low 44.39 / yr $37K
94 Butler County
6.9
Very Low 40.82 / yr $36K
95 Franklin County
6.1
Very Low 40.63 / yr $27K
96 Adams County
5.2
Very Low 45.20 / yr $18K
97 Ringgold County
5.0
Very Low 45.34 / yr $23K
98 Grundy County
3.4
Very Low 42.51 / yr $20K
99 Worth County
3.1
Very Low 40.33 / yr $15K

99 Iowa counties with measurable lightning risk. See the national lightning ranking or all Iowa counties by overall risk.

Frequently Asked Questions

Which Iowa county has the highest lightning risk?

Linn County has the highest FEMA lightning risk score in Iowa at 85.1 (High), with $1M in expected annual losses and about 42.84 events per year.

How many Iowa counties face significant lightning risk?

99 Iowa counties record measurable lightning risk in FEMA's National Risk Index; 2 of them are rated High or Very High.

Other Hazards in Iowa

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