Alaska volcanic activity risk

28 counties scored 0 rated Very High

Aleutians West Census Area has the highest volcanic activity risk in Alaska, scoring 98.7 out of 100 — rated "Relatively High" by FEMA's National Risk Index.

#	County	NRI score	Rating
1	Aleutians West Census Area	98.7	Relatively High
2	Aleutians East Borough	97.7	Relatively High
3	Sitka City and Borough	93.8	Relatively Moderate
4	Prince of Wales-Hyder Census Area	90.9	Relatively Low
5	Lake and Peninsula Borough	90.2	Relatively Low
6	Kenai Peninsula Borough	89.9	Relatively Low
7	Nome Census Area	89.6	Relatively Low
8	Anchorage Municipality	87.3	Relatively Low
9	Petersburg Borough	86.3	Relatively Low
10	Matanuska-Susitna Borough	80.8	Very Low
11	Ketchikan Gateway Borough	80.1	Very Low
12	Denali Borough	71.3	Very Low
13	Wrangell City and Borough	67.8	Very Low
14	Kodiak Island Borough	65.8	Very Low
15	Copper River Census Area	63.8	Very Low
16	Dillingham Census Area	61.9	Very Low
17	Fairbanks North Star Borough	53.4	Very Low
18	Juneau City and Borough	50.5	Very Low
19	Bristol Bay Borough	46.3	Very Low
20	Southeast Fairbanks Census Area	42.3	Very Low
21	Bethel Census Area	42	Very Low
22	Yukon-Koyukuk Census Area	40.4	Very Low
23	Kusilvak Census Area	34.5	Very Low
24	Hoonah-Angoon Census Area	30	Very Low
25	Northwest Arctic Borough	29.3	Very Low
26	Haines Borough	16	Very Low
27	Chugach Census Area	0	No Rating
28	Yakutat City and Borough	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:

Top 50 US counties

Other hazard risks in Alaska:

Wildfire Inland Flooding Coastal Flooding Earthquake Heat Wave Tornado Hurricane Hail Strong Wind Winter Weather Ice Storm Cold Wave Lightning Drought Landslide Avalanche Tsunami

Frequently asked questions

What is the highest volcanic activity risk county in Alaska?

Aleutians West Census Area, AK has the highest volcanic activity risk in Alaska, with a FEMA National Risk Index score of 98.7 out of 100 (rated "Relatively High").

What causes volcanic activity risk in Alaska?

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.