Volcanic activity risk by county
Ash, lava and mudflows from active volcanoes, mainly in Hawaii, Alaska and the Cascades.
Highest expected losses
| # | County | Rating | A year |
|---|---|---|---|
| 1 | Hawaii County, HI | $26M | |
| 2 | Cowlitz County, WA | $8M | |
| 3 | Pierce County, WA | $7M | |
| 4 | Skagit County, WA | $3M | |
| 5 | Aleutians West Census Area, AK | $3M | |
| 6 | Maui County, HI | $2M | |
| 7 | King County, WA | $2M | |
| 8 | Skamania County, WA | $2M | |
| 9 | Siskiyou County, CA | $2M | |
| 10 | Aleutians East Borough, AK | $895K | |
| 11 | Snohomish County, WA | $675K | |
| 12 | Deschutes County, OR | $554K | |
| 13 | Clackamas County, OR | $495K | |
| 14 | Hood River County, OR | $491K | |
| 15 | Lake County, CA | $484K |
Big counties lead this list partly because they have more people and buildings at risk.
Highest per resident
| # | County (100,000+ people) | Per person a year |
|---|---|---|
| 1 | Hawaii County, HI | $131 |
| 2 | Cowlitz County, WA | $68 |
| 3 | Skagit County, WA | $26 |
| 4 | Maui County, HI | $15 |
| 5 | Pierce County, WA | $7 |
| 6 | Deschutes County, OR | $3 |
| 7 | Shasta County, CA | $1 |
| 8 | Clackamas County, OR | $1 |
| 9 | King County, WA | $1 |
| 10 | Snohomish County, WA | $1 |
Expected yearly loss divided by population. A fairer way to compare places of different size.
Lowest risk among large counties
| # | County (250,000+ people) | Rating | Per person a year |
|---|---|---|---|
| 1 | Santa Clara County, CA | under $1 | |
| 2 | Bernalillo County, NM | under $1 | |
| 3 | San Diego County, CA | under $1 | |
| 4 | San Francisco County, CA | under $1 | |
| 5 | San Bernardino County, CA | under $1 | |
| 6 | Clark County, NV | under $1 | |
| 7 | Fresno County, CA | under $1 | |
| 8 | Kern County, CA | under $1 | |
| 9 | Riverside County, CA | under $1 | |
| 10 | Merced County, CA | under $1 |
How ratings are spread
The lists above show only the top counties, so they are all rated high. Across all 283 rated counties, most are Low or Very Low:
How to prepare
- Follow USGS volcano alerts.
- Keep masks and goggles for ash fall.
- Learn mudflow evacuation routes in Cascade river valleys.
Common questions
Which US county has the highest volcanic activity risk?
Hawaii County, HI has the highest expected yearly volcanic activity losses in FEMA's National Risk Index, about $26.3 million a year. Cowlitz County, WA is second at $7.6 million.
How many counties face volcanic activity risk?
FEMA rates volcanic activity in 283 of 3,144 counties in the 50 states and DC. 1 are rated Very High and 9 Relatively High.
Is volcanic activity covered by home insurance?
Usually yes for damage to the home, but check deductibles. Some states and insurers use separate wind, hail or hurricane deductibles.
Other hazards
Source: FEMA National Risk Index (December 2025). Expected annual loss is FEMA's long-run estimate of yearly damage to buildings, people and farm output, in dollars.