Utah volcanic activity risk
Kane County has the highest volcanic activity risk in Utah, scoring 76.2 out of 100 — rated "Very Low" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Kane County | 76.2 | Very Low |
| 2 | Garfield County | 75.9 | Very Low |
| 3 | Salt Lake County | 75.2 | Very Low |
| 4 | Iron County | 74.9 | Very Low |
| 5 | Millard County | 73.9 | Very Low |
| 6 | Utah County | 70.7 | Very Low |
| 7 | Washington County | 65.5 | Very Low |
| 8 | Sanpete County | 48.5 | Very Low |
| 9 | Davis County | 45.6 | Very Low |
| 10 | Sevier County | 43 | Very Low |
| 11 | Summit County | 39.1 | Very Low |
| 12 | Wasatch County | 38.4 | Very Low |
| 13 | Carbon County | 37.5 | Very Low |
| 14 | Emery County | 36.2 | Very Low |
| 15 | Beaver County | 34.2 | Very Low |
| 16 | Juab County | 30.3 | Very Low |
| 17 | Wayne County | 26.7 | Very Low |
| 18 | Duchesne County | 26.4 | Very Low |
| 19 | Piute County | 24.8 | Very Low |
| 20 | San Juan County | 20.8 | Very Low |
| 21 | Morgan County | 15.6 | Very Low |
| 22 | Tooele County | 14.3 | Very Low |
| 23 | Box Elder County | 10.1 | Very Low |
| 24 | Grand County | 0 | No Rating |
| 25 | Uintah 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 Utah:
Frequently asked questions
What is the highest volcanic activity risk county in Utah?
Kane County, UT has the highest volcanic activity risk in Utah, with a FEMA National Risk Index score of 76.2 out of 100 (rated "Very Low").
What causes volcanic activity risk in Utah?
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.