Riverine Flood Risk in Alaska

All Alaska counties ranked by FEMA National Risk Index riverine flood score

Riverine Flood risk — rivers and streams overflowing their banks after heavy rain or snowmelt — is rated for 26 of 30 Alaska counties in FEMA's National Risk Index. Matanuska-Susitna Borough carries the state's highest riverine flood score at 51.3, with $8M in expected annual riverine flood losses.

No Alaska county reaches the High band for riverine flood, and expected annual losses from riverine flood total roughly $30M statewide. The full ranking below links to each county's complete 18-hazard risk profile.

County Rankings — Riverine Flood

#CountyRiverine Flood ScoreRatingAnn. Freq.Ann. Loss
1 Matanuska-Susitna Borough
51.3
Low 0.01 / yr $8M
2 Fairbanks North Star Borough
45.7
Low 0.01 / yr $8M
3 Kenai Peninsula Borough
43.8
Low 0.01 / yr $5M
4 Juneau City and Borough
12.2
Very Low 0.01 / yr $2M
5 Bethel Census Area
9.6
Very Low 0.01 / yr $759K
6 Southeast Fairbanks Census Area
9.4
Very Low 0.01 / yr $793K
7 Yukon-Koyukuk Census Area
6.6
Very Low 0.01 / yr $527K
8 Nome Census Area
5.7
Very Low 0.01 / yr $470K
9 Ketchikan Gateway Borough
4.5
Very Low 0.01 / yr $722K
10 Kodiak Island Borough
4.4
Very Low 0.01 / yr $670K
11 Prince of Wales-Hyder Census Area
3.8
Very Low 0.01 / yr $372K
12 Northwest Arctic Borough
3.4
Very Low 0.01 / yr $302K
13 Dillingham Census Area
3.1
Very Low 0.01 / yr $302K
14 Sitka City and Borough
2.6
Very Low 0.50 / yr $415K
15 North Slope Borough
2.6
Very Low 0.04 / yr $378K
16 Copper River Census Area
1.9
Very Low 0.01 / yr $235K
17 Denali Borough
1.5
Very Low 0.01 / yr $361K
18 Hoonah-Angoon Census Area
1.3
Very Low 0.01 / yr $160K
19 Petersburg Borough
1.0
Very Low 0.01 / yr $187K
20 Chugach Census Area
0.8
Very Low 0.01 / yr $266K
21 Haines Borough
0.8
Very Low 0.01 / yr $177K
22 Wrangell City and Borough
0.4
Very Low 0.01 / yr $101K
23 Yakutat City and Borough
0.3
Very Low 0.01 / yr $50K
24 Skagway Municipality
0.3
Very Low 0.01 / yr $33K
25 Anchorage Municipality
0.2
Very Low 0.04 / yr $397
26 Lake and Peninsula Borough
0.2
Very Low 0.01 / yr $0

26 Alaska counties with measurable riverine flood risk. See the national riverine flood ranking or all Alaska counties by overall risk.

Frequently Asked Questions

Which Alaska county has the highest riverine flood risk?

Matanuska-Susitna Borough has the highest FEMA riverine flood risk score in Alaska at 51.3 (Low), with $8M in expected annual losses and about 0.01 events per year.

How many Alaska counties face significant riverine flood risk?

26 Alaska counties record measurable riverine flood risk in FEMA's National Risk Index; 0 of them are rated High or Very High.

Other Hazards in Alaska

Avalanche Coastal Flood Cold Wave Earthquake Hail Ice Storm Landslide Lightning Strong Wind Tornado Tsunami Volcanic Activity Wildfire Winter Weather