Riverine Flood Risk by State & County

Ranked by FEMA National Risk Index riverine flood hazard score · code IFLD

Riverine Flood risk reflects rivers and streams overflowing their banks after heavy rain or snowmelt. FEMA's National Risk Index scores each county's riverine flood hazard from its expected annual loss, annualized event frequency, and exposed population. Los Angeles County, California currently leads the nation with a riverine flood score of 100.0 and $2.81B in expected annual loss. California, Texas, Arizona account for much of the highest-rated riverine flood risk in this dataset.

Read the full riverine flood risk guide — how FEMA scores it and how to prepare →

Riverine Flood Risk by State

#StateExpected Ann. LossAvg. ScoreRatingCounties Rated
1California$11.66B
85.8
Very High 58 of 58
2Texas$4.94B
42.1
Medium 254 of 254
3Illinois$2.92B
52.4
Medium 102 of 102
4New York$2.79B
80.9
Very High 62 of 62
5Florida$2.78B
67.5
High 67 of 67
6Pennsylvania$2.73B
79.6
High 67 of 67
7North Carolina$2.05B
65.2
High 100 of 100
8New Jersey$1.99B
91.7
Very High 21 of 21
9Arizona$1.98B
87.3
Very High 15 of 15
10Ohio$1.95B
67.3
High 88 of 88
11Georgia$1.58B
40.3
Medium 159 of 159
12Missouri$1.57B
50.4
Medium 115 of 115
13Michigan$1.52B
56.7
Medium 83 of 83
14Washington$1.36B
70.0
High 39 of 39
15Minnesota$1.28B
49.1
Medium 87 of 87
16Kentucky$1.27B
50.6
Medium 120 of 120
17Indiana$1.21B
52.0
Medium 92 of 92
18Tennessee$1.18B
48.8
Medium 95 of 95
19Virginia$1.15B
41.1
Medium 133 of 133
20Wisconsin$1.12B
59.0
Medium 72 of 72
21Alabama$1.08B
62.6
High 67 of 67
22Colorado$960M
44.2
Medium 64 of 64
23Massachusetts$943M
81.9
Very High 14 of 14
24Louisiana$911M
53.1
Medium 64 of 64
25West Virginia$859M
69.2
High 55 of 55
26Connecticut$858M
92.2
Very High 9 of 9
27Oregon$852M
63.5
High 36 of 36
28South Carolina$785M
62.1
High 46 of 46
29Oklahoma$738M
44.0
Medium 77 of 77
30Iowa$725M
38.1
Low 99 of 99
31New Mexico$641M
65.4
High 33 of 33
32Kansas$634M
26.1
Low 105 of 105
33Arkansas$628M
50.3
Medium 75 of 75
34Hawaii$622M
76.6
High 5 of 5
35Nevada$517M
41.5
Medium 17 of 17
36Mississippi$500M
43.2
Medium 82 of 82
37Maryland$492M
56.9
Medium 24 of 24
38Nebraska$401M
20.3
Low 93 of 93
39Idaho$383M
43.2
Medium 44 of 44
40Utah$329M
32.1
Low 29 of 29
41New Hampshire$314M
79.9
High 10 of 10
42Montana$277M
31.9
Low 56 of 56
43South Dakota$274M
25.6
Low 66 of 66
44Delaware$217M
91.1
Very High 3 of 3
45Maine$181M
55.0
Medium 16 of 16
46Vermont$162M
54.4
Medium 14 of 14
47North Dakota$161M
16.1
Very Low 53 of 53
48Rhode Island$153M
68.4
High 5 of 5
49Wyoming$147M
42.3
Medium 23 of 23
50District of Columbia$130M
97.4
Very High 1 of 1
51Alaska$30M
7.2
Very Low 30 of 30

States ranked by total expected annual riverine flood losses; the average score is the mean over all counties, counting unrated counties as zero.

Riskiest Counties for Riverine Flood

#CountyStateRiverine Flood ScoreRatingAnn. Freq.Ann. Loss
1Los Angeles CountyCA
100.0
Very High 3.96 / yr$2.81B
2Harris CountyTX
100.0
Very High 5.14 / yr$1.12B
3Cook CountyIL
99.9
Very High 5.89 / yr$1.10B
4Maricopa CountyAZ
99.9
Very High 8.46 / yr$1.12B
5Riverside CountyCA
99.9
Very High 7.36 / yr$1.13B
6Orange CountyCA
99.8
Very High 2.89 / yr$820M
7San Bernardino CountyCA
99.8
Very High 12.96 / yr$960M
8Santa Clara CountyCA
99.8
Very High 2.07 / yr$720M
9Alameda CountyCA
99.7
Very High 2.25 / yr$491M
10San Diego CountyCA
99.7
Very High 7.89 / yr$648M
11Miami-Dade CountyFL
99.7
Very High 4.00 / yr$356M
12Bexar CountyTX
99.7
Very High 7.46 / yr$365M
13Dallas CountyTX
99.6
Very High 4.61 / yr$324M
14Clark CountyNV
99.6
Very High 7.25 / yr$362M
15Philadelphia CountyPA
99.6
Very High 5.82 / yr$266M
16King CountyWA
99.5
Very High 0.29 / yr$417M
17Contra Costa CountyCA
99.5
Very High 1.18 / yr$412M
18Pima CountyAZ
99.5
Very High 12.82 / yr$347M
19Broward CountyFL
99.4
Very High 2.46 / yr$289M
20Kings CountyNY
99.4
Very High 1.96 / yr$181M
21Wayne CountyMI
99.4
Very High 3.14 / yr$237M
22Ventura CountyCA
99.3
Very High 1.93 / yr$313M
23Queens CountyNY
99.3
Very High 3.29 / yr$185M
24Honolulu CountyHI
99.3
Very High 5.93 / yr$330M
25Sonoma CountyCA
99.2
High 2.54 / yr$280M

Showing the top 25 seeded counties for riverine flood risk.