Washington inland flooding risk
King County has the highest inland flooding risk in Washington, scoring 99.5 out of 100 — rated "Very High" by FEMA's National Risk Index. NOAA has recorded 269 inland flooding events across Washington over the past decade.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | King County | 99.5 | Very High | 1 |
| 2 | Pierce County | 96.2 | Relatively High | 0 |
| 3 | Snohomish County | 95.7 | Relatively High | 4 |
| 4 | Yakima County | 92.9 | Relatively Moderate | 11 |
| 5 | Clark County | 92.6 | Relatively Moderate | 7 |
| 6 | Spokane County | 91.6 | Relatively Moderate | 27 |
| 7 | Chelan County | 91.3 | Relatively Moderate | 35 |
| 8 | Lewis County | 90.9 | Relatively Moderate | 3 |
| 9 | Thurston County | 90.8 | Relatively Moderate | 2 |
| 10 | Benton County | 89.7 | Relatively Moderate | 3 |
| 11 | Okanogan County | 89.1 | Relatively Moderate | 37 |
| 12 | Whatcom County | 88.9 | Relatively Moderate | 2 |
| 13 | Cowlitz County | 88.3 | Relatively Moderate | 10 |
| 14 | Skagit County | 87.8 | Relatively Moderate | 3 |
| 15 | Grays Harbor County | 83.8 | Relatively Moderate | 3 |
| 16 | Franklin County | 83.5 | Relatively Moderate | 2 |
| 17 | Douglas County | 82.1 | Relatively Moderate | 6 |
| 18 | Mason County | 79.3 | Relatively Moderate | 2 |
| 19 | Kitsap County | 79.1 | Relatively Moderate | 0 |
| 20 | Grant County | 77.2 | Relatively Moderate | 4 |
| 21 | Clallam County | 75 | Relatively Moderate | 3 |
| 22 | Kittitas County | 74.8 | Relatively Moderate | 1 |
| 23 | Stevens County | 68.6 | Relatively Low | 10 |
| 24 | Klickitat County | 66.6 | Relatively Low | 1 |
| 25 | Walla Walla County | 64.8 | Relatively Low | 10 |
| 26 | Pacific County | 63.3 | Relatively Low | 4 |
| 27 | Whitman County | 58.8 | Relatively Low | 23 |
| 28 | Island County | 54.9 | Relatively Low | 0 |
| 29 | Pend Oreille County | 54.3 | Relatively Low | 5 |
| 30 | Jefferson County | 53.7 | Relatively Low | 1 |
| 31 | Ferry County | 52.3 | Relatively Low | 18 |
| 32 | Lincoln County | 50 | Relatively Low | 5 |
| 33 | Skamania County | 49.8 | Relatively Low | 0 |
| 34 | San Juan County | 42.1 | Relatively Low | 1 |
| 35 | Asotin County | 38.5 | Relatively Low | 5 |
| 36 | Adams County | 34.3 | Very Low | 2 |
| 37 | Columbia County | 30.7 | Very Low | 3 |
| 38 | Wahkiakum County | 17.6 | Very Low | 20 |
| 39 | Garfield County | 10.3 | Very Low | 2 |
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 Washington:
Frequently asked questions
What is the highest inland flooding risk county in Washington?
King County, WA has the highest inland flooding risk in Washington, with a FEMA National Risk Index score of 99.5 out of 100 (rated "Very High").
How many counties in Washington are rated Very High for inland flooding risk?
1 of 39 scored Washington counties are rated "Very High" for inland flooding risk by FEMA's National Risk Index.
What causes inland flooding risk in Washington?
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.