Alaska: basement moisture and foundation risk by county
29 counties, ranked by our combined index. Highest combined risk is Nome Census Area (52), lowest is Kenai Peninsula Borough (38). The worst soil for foundation cracks specifically is in Wrangell City and Borough.
| County | Index | Moisture | Cracks | Water table | Region |
|---|---|---|---|---|---|
| Nome Census Area | 52 | 48 | 37 | 82 | Alaska: permafrost and frost-susceptible ground |
| Skagway Municipality | 51 | 48 | 34 | 82 | Alaska: permafrost and frost-susceptible ground |
| Ketchikan Gateway Borough | 50 | 49 | 28 | 82 | Alaska: permafrost and frost-susceptible ground |
| Kusilvak Census Area | 50 | 47 | 30 | 82 | Alaska: permafrost and frost-susceptible ground |
| Aleutians West Census Area | 48 | 50 | 31 | 66 | Alaska: permafrost and frost-susceptible ground |
| Kodiak Island Borough | 48 | 51 | 20 | 82 | Alaska: permafrost and frost-susceptible ground |
| North Slope Borough | 48 | 49 | 21 | 82 | Alaska: permafrost and frost-susceptible ground |
| Matanuska-Susitna Borough | 47 | 48 | 32 | 66 | Alaska: permafrost and frost-susceptible ground |
| Aleutians East Borough | 46 | 47 | 29 | 66 | Alaska: permafrost and frost-susceptible ground |
| Dillingham Census Area | 46 | 51 | 24 | 66 | Alaska: permafrost and frost-susceptible ground |
| Northwest Arctic Borough | 46 | 51 | 14 | 82 | Alaska: permafrost and frost-susceptible ground |
| Petersburg Borough | 45 | 49 | 25 | 66 | Alaska: permafrost and frost-susceptible ground |
| Wrangell City and Borough | 45 | 50 | 38 | 46 | Alaska: permafrost and frost-susceptible ground |
| Lake and Peninsula Borough | 44 | 50 | 34 | 46 | Alaska: permafrost and frost-susceptible ground |
| Sitka City and Borough | 44 | 50 | 20 | 66 | Alaska: permafrost and frost-susceptible ground |
| Anchorage Municipality | 43 | 48 | 34 | 46 | Alaska: permafrost and frost-susceptible ground |
| Haines Borough | 43 | 50 | 18 | 66 | Alaska: permafrost and frost-susceptible ground |
| Juneau City and Borough | 43 | 50 | 30 | 46 | Alaska: permafrost and frost-susceptible ground |
| Prince of Wales-Hyder Census Area | 43 | 51 | 29 | 46 | Alaska: permafrost and frost-susceptible ground |
| Southeast Fairbanks Census Area | 43 | 51 | 16 | 66 | Alaska: permafrost and frost-susceptible ground |
| Copper River Census Area | 42 | 49 | 30 | 46 | Alaska: permafrost and frost-susceptible ground |
| Denali Borough | 42 | 51 | 28 | 46 | Alaska: permafrost and frost-susceptible ground |
| Hoonah-Angoon Census Area | 42 | 49 | 30 | 46 | Alaska: permafrost and frost-susceptible ground |
| Bethel Census Area | 41 | 51 | 24 | 46 | Alaska: permafrost and frost-susceptible ground |
| Fairbanks North Star Borough | 41 | 50 | 25 | 46 | Alaska: permafrost and frost-susceptible ground |
| Yakutat City and Borough | 41 | 51 | 24 | 46 | Alaska: permafrost and frost-susceptible ground |
| Bristol Bay Borough | 39 | 49 | 20 | 46 | Alaska: permafrost and frost-susceptible ground |
| Kenai Peninsula Borough | 38 | 50 | 16 | 46 | Alaska: permafrost and frost-susceptible ground |
| Yukon-Koyukuk Census Area | 38 | 49 | 17 | 46 | Alaska: permafrost and frost-susceptible ground |
Values from USDA NRCS SSURGO where available, otherwise our regional model — each county page states which. Methodology.
The physiographic regions inside Alaska
State lines are political; soil follows geology. These are the distinct ground types inside Alaska and why each behaves the way it does.
Alaska: permafrost and frost-susceptible ground
A different physics from the rest of the country. Frost heave and thawing permafrost move foundations far more than shrink-swell does, and a heated basement is itself a hazard where permafrost is present, because the heat thaws the ground it sits on. Local engineering practice, not national rules of thumb, governs here.
29 counties: Aleutians East Borough, Aleutians West Census Area, Anchorage Municipality, Bethel Census Area, Bristol Bay Borough, Copper River Census Area, Denali Borough, Dillingham Census Area, Fairbanks North Star Borough, Haines Borough, Hoonah-Angoon Census Area, Juneau City and Borough, Kenai Peninsula Borough, Ketchikan Gateway Borough, Kodiak Island Borough, Kusilvak Census Area, Lake and Peninsula Borough, Matanuska-Susitna Borough, Nome Census Area, North Slope Borough, Northwest Arctic Borough, Petersburg Borough, Prince of Wales-Hyder Census Area, Sitka City and Borough, Skagway Municipality, Southeast Fairbanks Census Area, Wrangell City and Borough, Yakutat City and Borough, Yukon-Koyukuk Census Area
Page data updated