Alaska inland flooding risk

30 counties scored 0 rated Very High

Matanuska-Susitna Borough has the highest inland flooding risk in Alaska, scoring 51.3 out of 100 — rated "Relatively Low" by FEMA's National Risk Index.

#	County	NRI score	Rating	NOAA events 2016–2026
1	Matanuska-Susitna Borough	51.3	Relatively Low	0
2	Fairbanks North Star Borough	45.7	Relatively Low	0
3	Kenai Peninsula Borough	43.8	Relatively Low	0
4	Juneau City and Borough	12.2	Very Low	0
5	Bethel Census Area	9.6	Very Low	0
6	Southeast Fairbanks Census Area	9.4	Very Low	0
7	Yukon-Koyukuk Census Area	6.6	Very Low	0
8	Nome Census Area	5.7	Very Low	0
9	Ketchikan Gateway Borough	4.5	Very Low	0
10	Kodiak Island Borough	4.4	Very Low	0
11	Prince of Wales-Hyder Census Area	3.8	Very Low	0
12	Northwest Arctic Borough	3.4	Very Low	0
13	Dillingham Census Area	3.1	Very Low	0
14	North Slope Borough	2.6	Very Low	1
15	Sitka City and Borough	2.6	Very Low	6
16	Copper River Census Area	1.9	Very Low	0
17	Denali Borough	1.5	Very Low	0
18	Hoonah-Angoon Census Area	1.3	Very Low	0
19	Petersburg Borough	1	Very Low	0
20	Chugach Census Area	0.8	Very Low	0
21	Haines Borough	0.8	Very Low	0
22	Wrangell City and Borough	0.4	Very Low	0
23	Skagway Municipality	0.3	Very Low	0
24	Yakutat City and Borough	0.3	Very Low	0
25	Anchorage Municipality	0.2	Very Low	1
26	Lake and Peninsula Borough	0.2	Very Low	0
27	Aleutians East Borough	0	No Rating	0
28	Aleutians West Census Area	0	No Rating	0
29	Bristol Bay Borough	0	No Rating	0
30	Kusilvak Census Area	0	No Rating	0

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.

Inland Flooding risk nationally:

Top 50 US counties

Other hazard risks in Alaska:

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

Frequently asked questions

What is the highest inland flooding risk county in Alaska?

Matanuska-Susitna Borough, AK has the highest inland flooding risk in Alaska, with a FEMA National Risk Index score of 51.3 out of 100 (rated "Relatively Low").

What causes inland flooding risk in Alaska?

Inland flooding covers riverine and surface (pluvial) flooding — the most common and costly natural disaster type in the US. High scores appear across river floodplains in the Midwest, South, and Mid-Atlantic, where legacy development in flood-prone areas and aging stormwater infrastructure concentrate risk.