FEMA National Risk Index hazard
Prepare your home for volcanic activity
Eruptions and related hazards such as ashfall and lahars.
10 US counties are rated Relatively High or Very High for volcanic activity by FEMA’s National Risk Index. The three things that matter most at home: 1. Know if you are in a lahar or ashfall zone. 2. Keep N95 masks and goggles for ash. 3. Have a plan to protect the HVAC system from ash.
Before the season
- Learn the local volcano alert levels and evacuation routes.
- Store spare HVAC filters.
- Keep plastic sheeting to cover electronics.
When a warning comes
- Follow evacuation orders.
- Close windows and doors; turn off HVAC fans.
- Stay indoors during ashfall.
After
- Clear ash from roofs carefully; wet ash is heavy.
- Replace HVAC filters.
- Keep ash out of drains and gutters.
Ask your insurer
Ask how volcanic ash and eruption damage is treated by your policy. We explain and organize; we never predict coverage.
Ready.gov: Volcanoes Checklist: original casaq guidance
Counties with the highest volcanic activity scores
Top 25 by FEMA NRI risk score for this hazard. Scores and ratings are relative to other US counties, not probabilities of a loss.
| # | County | Rating | Score | Recorded events |
|---|---|---|---|---|
| 1 | Hawaii County, HI | Very High | 100.0 | 5 |
| 2 | Cowlitz County, WA | Relatively High | 99.7 | 6 |
| 3 | Pierce County, WA | Relatively High | 99.3 | 6 |
| 4 | Skagit County, WA | Relatively High | 99.0 | 3 |
| 5 | Aleutians West Census Area, AK | Relatively High | 98.7 | 30 |
| 6 | Maui County, HI | Relatively High | 98.4 | 1 |
| 7 | Siskiyou County, CA | Relatively High | 98.0 | 4 |
| 8 | Aleutians East Borough, AK | Relatively High | 97.7 | 21 |
| 9 | King County, WA | Relatively High | 97.4 | 6 |
| 10 | Skamania County, WA | Relatively High | 97.1 | 11 |
| 11 | Lake County, CA | Relatively Moderate | 96.7 | 1 |
| 12 | Snohomish County, WA | Relatively Moderate | 96.4 | 5 |
| 13 | Deschutes County, OR | Relatively Moderate | 96.1 | 11 |
| 14 | Clackamas County, OR | Relatively Moderate | 95.8 | 11 |
| 15 | Hood River County, OR | Relatively Moderate | 95.4 | 10 |
| 16 | Lewis County, WA | Relatively Moderate | 95.1 | 7 |
| 17 | Shasta County, CA | Relatively Moderate | 94.8 | 3 |
| 18 | Lane County, OR | Relatively Moderate | 94.5 | 12 |
| 19 | Thurston County, WA | Relatively Moderate | 94.1 | 5 |
| 20 | Sitka City and Borough, AK | Relatively Moderate | 93.8 | 1 |
| 21 | Multnomah County, OR | Relatively Moderate | 93.5 | 7 |
| 22 | Whatcom County, WA | Relatively Moderate | 93.2 | 3 |
| 23 | Marion County, OR | Relatively Moderate | 92.8 | 10 |
| 24 | Klickitat County, WA | Relatively Low | 92.2 | 12 |
| 25 | Linn County, OR | Relatively Low | 91.9 | 12 |