Washington volcanic activity risk
Cowlitz County has the highest volcanic activity risk in Washington, scoring 99.7 out of 100 — rated "Relatively High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Cowlitz County | 99.7 | Relatively High |
| 2 | Pierce County | 99.3 | Relatively High |
| 3 | Skagit County | 99 | Relatively High |
| 4 | King County | 97.4 | Relatively High |
| 5 | Skamania County | 97.1 | Relatively High |
| 6 | Snohomish County | 96.4 | Relatively Moderate |
| 7 | Lewis County | 95.1 | Relatively Moderate |
| 8 | Thurston County | 94.1 | Relatively Moderate |
| 9 | Whatcom County | 93.2 | Relatively Moderate |
| 10 | Klickitat County | 92.2 | Relatively Low |
| 11 | Chelan County | 90.6 | Relatively Low |
| 12 | Clark County | 88.6 | Relatively Low |
| 13 | Yakima County | 87.9 | Relatively Low |
| 14 | Island County | 84.7 | Relatively Low |
| 15 | Douglas County | 83.4 | Very Low |
| 16 | Kittitas County | 83.1 | Very Low |
| 17 | Grant County | 82.4 | Very Low |
| 18 | Benton County | 81.1 | Very Low |
| 19 | Okanogan County | 76.9 | Very Low |
| 20 | Franklin County | 75.6 | Very Low |
| 21 | Wahkiakum County | 69.7 | Very Low |
| 22 | Kitsap County | 68.4 | Very Low |
| 23 | Ferry County | 54.4 | Very Low |
| 24 | Mason County | 48.2 | Very Low |
| 25 | Adams County | 43.3 | Very Low |
| 26 | San Juan County | 37.1 | Very Low |
| 27 | Lincoln County | 13.7 | Very Low |
| 28 | Jefferson County | 11.4 | Very Low |
| 29 | Pacific County | 9.8 | Very Low |
| 30 | Clallam County | 0 | No Rating |
| 31 | Grays Harbor County | 0 | No Rating |
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.
Volcanic Activity risk nationally:
Other hazard risks in Washington:
Frequently asked questions
What is the highest volcanic activity risk county in Washington?
Cowlitz County, WA has the highest volcanic activity risk in Washington, with a FEMA National Risk Index score of 99.7 out of 100 (rated "Relatively High").
What causes volcanic activity risk in Washington?
Volcanic activity risk reflects expected losses from lava flows, tephra fall, lahars (volcanic mudflows), and volcanic gases. The highest-risk counties are in Washington (Mt. Rainier), Oregon (Mt. Hood), and Hawaii (Kilauea, Mauna Loa). Alaska's Aleutian chain contains many active volcanoes affecting nearby communities and trans-Pacific air traffic. Volcanic ashfall events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.