Riverine Flood Risk in South Dakota
All South Dakota counties ranked by FEMA National Risk Index riverine flood score
Riverine Flood risk — rivers and streams overflowing their banks after heavy rain or snowmelt — is rated for 66 of 66 South Dakota counties in FEMA's National Risk Index. Minnehaha County carries the state's highest riverine flood score at 85.5, with $34M in expected annual riverine flood losses.
No South Dakota county reaches the High band for riverine flood, and expected annual losses from riverine flood total roughly $274M statewide. The full ranking below links to each county's complete 18-hazard risk profile.
County Rankings — Riverine Flood
| # | County | Riverine Flood Score | Rating | Ann. Freq. | Ann. Loss |
|---|---|---|---|---|---|
| 1 | Minnehaha County | Medium | 4.50 / yr | $34M | |
| 2 | Pennington County | Medium | 2.07 / yr | $17M | |
| 3 | Codington County | Low | 1.68 / yr | $12M | |
| 4 | Brown County | Low | 5.18 / yr | $11M | |
| 5 | McCook County | Low | 0.79 / yr | $13M | |
| 6 | Yankton County | Low | 2.32 / yr | $7M | |
| 7 | Lawrence County | Low | 0.75 / yr | $8M | |
| 8 | Lincoln County | Low | 2.71 / yr | $15M | |
| 9 | Meade County | Low | 1.39 / yr | $10M | |
| 10 | Brookings County | Low | 2.75 / yr | $9M | |
| 11 | Union County | Low | 3.61 / yr | $9M | |
| 12 | Beadle County | Low | 2.50 / yr | $6M | |
| 13 | Fall River County | Low | 0.96 / yr | $3M | |
| 14 | Charles Mix County | Low | 1.71 / yr | $4M | |
| 15 | Roberts County | Low | 1.32 / yr | $3M | |
| 16 | Tripp County | Low | 0.93 / yr | $3M | |
| 17 | Davison County | Low | 3.14 / yr | $5M | |
| 18 | Hutchinson County | Low | 2.79 / yr | $5M | |
| 19 | Walworth County | Very Low | 0.61 / yr | $3M | |
| 20 | Lake County | Very Low | 0.68 / yr | $4M | |
| 21 | Butte County | Very Low | 0.71 / yr | $4M | |
| 22 | Hughes County | Very Low | 1.14 / yr | $6M | |
| 23 | Lyman County | Very Low | 1.14 / yr | $2M | |
| 24 | Clay County | Very Low | 2.11 / yr | $5M | |
| 25 | Brule County | Very Low | 0.89 / yr | $3M | |
| 26 | Todd County | Very Low | 0.57 / yr | $2M | |
| 27 | Turner County | Very Low | 1.64 / yr | $4M | |
| 28 | Moody County | Very Low | 2.11 / yr | $3M | |
| 29 | Spink County | Very Low | 3.32 / yr | $4M | |
| 30 | Haakon County | Very Low | 0.96 / yr | $2M | |
| 31 | Day County | Very Low | 1.11 / yr | $2M | |
| 32 | Stanley County | Very Low | 0.96 / yr | $3M | |
| 33 | Custer County | Very Low | 1.18 / yr | $3M | |
| 34 | Oglala Lakota County | Very Low | 0.86 / yr | $1M | |
| 35 | Dewey County | Very Low | 0.96 / yr | $1M | |
| 36 | Grant County | Very Low | 1.04 / yr | $3M | |
| 37 | Corson County | Very Low | 1.71 / yr | $1M | |
| 38 | Hamlin County | Very Low | 1.93 / yr | $3M | |
| 39 | Gregory County | Very Low | 0.46 / yr | $2M | |
| 40 | Hanson County | Very Low | 2.21 / yr | $1M | |
| 41 | Potter County | Very Low | 0.64 / yr | $2M | |
| 42 | Sully County | Very Low | 0.50 / yr | $3M | |
| 43 | Jackson County | Very Low | 1.00 / yr | $892K | |
| 44 | Aurora County | Very Low | 0.61 / yr | $2M | |
| 45 | Hyde County | Very Low | 0.71 / yr | $1M | |
| 46 | Buffalo County | Very Low | 0.57 / yr | $1M | |
| 47 | Douglas County | Very Low | 0.64 / yr | $2M | |
| 48 | Marshall County | Very Low | 0.93 / yr | $1M | |
| 49 | Kingsbury County | Very Low | 0.57 / yr | $2M | |
| 50 | Deuel County | Very Low | 0.57 / yr | $2M | |
| 51 | Ziebach County | Very Low | 1.18 / yr | $640K | |
| 52 | Bon Homme County | Very Low | 2.43 / yr | $2M | |
| 53 | Campbell County | Very Low | 0.46 / yr | $2M | |
| 54 | Jerauld County | Very Low | 0.29 / yr | $1M | |
| 55 | Mellette County | Very Low | 0.54 / yr | $657K | |
| 56 | McPherson County | Very Low | 0.64 / yr | $788K | |
| 57 | Edmunds County | Very Low | 1.00 / yr | $2M | |
| 58 | Faulk County | Very Low | 0.68 / yr | $641K | |
| 59 | Hand County | Very Low | 1.21 / yr | $1M | |
| 60 | Sanborn County | Very Low | 2.43 / yr | $1M | |
| 61 | Clark County | Very Low | 0.75 / yr | $1M | |
| 62 | Jones County | Very Low | 0.82 / yr | $950K | |
| 63 | Perkins County | Very Low | 0.96 / yr | $920K | |
| 64 | Bennett County | Very Low | 0.43 / yr | $371K | |
| 65 | Miner County | Very Low | 0.36 / yr | $1M | |
| 66 | Harding County | Very Low | 0.64 / yr | $772K |
66 South Dakota counties with measurable riverine flood risk. See the national riverine flood ranking or all South Dakota counties by overall risk.
Frequently Asked Questions
Which South Dakota county has the highest riverine flood risk?
Minnehaha County has the highest FEMA riverine flood risk score in South Dakota at 85.5 (Medium), with $34M in expected annual losses and about 4.50 events per year.
How many South Dakota counties face significant riverine flood risk?
66 South Dakota counties record measurable riverine flood risk in FEMA's National Risk Index; 0 of them are rated High or Very High.