North Dakota inland flooding risk
Cass County has the highest inland flooding risk in North Dakota, scoring 80.6 out of 100 — rated "Relatively Moderate" by FEMA's National Risk Index. Recorded inland flooding events across North Dakota have increased 47% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Cass County | 80.6 | Relatively Moderate | 18 |
| 2 | Burleigh County | 77.4 | Relatively Moderate | 6 |
| 3 | Grand Forks County | 61.7 | Relatively Low | 21 |
| 4 | Williams County | 42.9 | Relatively Low | 1 |
| 5 | Ward County | 41.9 | Relatively Low | 1 |
| 6 | Barnes County | 41.3 | Relatively Low | 1 |
| 7 | Morton County | 40.4 | Relatively Low | 3 |
| 8 | Walsh County | 35.4 | Relatively Low | 6 |
| 9 | McLean County | 33.1 | Very Low | 1 |
| 10 | Emmons County | 30.9 | Very Low | 3 |
| 11 | Richland County | 29.5 | Very Low | 7 |
| 12 | Pembina County | 28.7 | Very Low | 15 |
| 13 | Stutsman County | 26.9 | Very Low | 3 |
| 14 | Stark County | 22.3 | Very Low | 1 |
| 15 | Rolette County | 21.6 | Very Low | 1 |
| 16 | Mercer County | 16.4 | Very Low | 2 |
| 17 | McKenzie County | 15.3 | Very Low | 1 |
| 18 | Ransom County | 14.3 | Very Low | 4 |
| 19 | Traill County | 12.7 | Very Low | 5 |
| 20 | Mountrail County | 11.9 | Very Low | 1 |
| 21 | Bottineau County | 11.6 | Very Low | 0 |
| 22 | McIntosh County | 10.8 | Very Low | 1 |
| 23 | Dunn County | 10.1 | Very Low | 2 |
| 24 | Ramsey County | 10 | Very Low | 3 |
| 25 | Sioux County | 10 | Very Low | 1 |
| 26 | Hettinger County | 9.7 | Very Low | 3 |
| 27 | McHenry County | 8.1 | Very Low | 1 |
| 28 | Cavalier County | 6.8 | Very Low | 3 |
| 29 | Benson County | 6.7 | Very Low | 3 |
| 30 | Grant County | 6.7 | Very Low | 1 |
| 31 | Dickey County | 6.5 | Very Low | 3 |
| 32 | Oliver County | 6.5 | Very Low | 1 |
| 33 | Divide County | 6.1 | Very Low | 0 |
| 34 | Logan County | 5.9 | Very Low | 0 |
| 35 | LaMoure County | 5.5 | Very Low | 2 |
| 36 | Wells County | 4.9 | Very Low | 5 |
| 37 | Nelson County | 4.3 | Very Low | 2 |
| 38 | Sheridan County | 4.1 | Very Low | 1 |
| 39 | Foster County | 3.2 | Very Low | 1 |
| 40 | Golden Valley County | 3.1 | Very Low | 1 |
| 41 | Kidder County | 3.1 | Very Low | 1 |
| 42 | Billings County | 3 | Very Low | 1 |
| 43 | Sargent County | 2.7 | Very Low | 1 |
| 44 | Adams County | 2.5 | Very Low | 1 |
| 45 | Pierce County | 2.5 | Very Low | 1 |
| 46 | Bowman County | 2.4 | Very Low | 0 |
| 47 | Steele County | 2.3 | Very Low | 2 |
| 48 | Burke County | 1.7 | Very Low | 1 |
| 49 | Griggs County | 1.7 | Very Low | 0 |
| 50 | Renville County | 1.7 | Very Low | 0 |
| 51 | Eddy County | 1.4 | Very Low | 2 |
| 52 | Towner County | 1.1 | Very Low | 3 |
| 53 | Slope County | 0.6 | Very Low | 0 |
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.
Inland Flooding risk nationally:
Other hazard risks in North Dakota:
Frequently asked questions
What is the highest inland flooding risk county in North Dakota?
Cass County, ND has the highest inland flooding risk in North Dakota, with a FEMA National Risk Index score of 80.6 out of 100 (rated "Relatively Moderate").
What causes inland flooding risk in North Dakota?
Inland flooding covers riverine and surface (pluvial) flooding — the most common and costly natural disaster type in the US. High scores appear across river floodplains in the Midwest, South, and Mid-Atlantic, where legacy development in flood-prone areas and aging stormwater infrastructure concentrate risk.