BasementSoil

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.

Where in Alaska the ground is worse

Every county in the state, coloured by the soil values below. Click a county to open its report; switch what the colour means with the buttons. The pattern is geology, not administration — risk stops at the edge of a physiographic region, not at a county line.

Aleutians East Borough, AK — combined 46/100, moisture 47, movement 29, water table 66Aleutians West Census Area, AK — combined 48/100, moisture 50, movement 31, water table 66Anchorage Municipality, AK — combined 43/100, moisture 48, movement 34, water table 46Bethel Census Area, AK — combined 41/100, moisture 51, movement 24, water table 46Bristol Bay Borough, AK — combined 39/100, moisture 49, movement 20, water table 46Denali Borough, AK — combined 42/100, moisture 51, movement 28, water table 46Dillingham Census Area, AK — combined 46/100, moisture 51, movement 24, water table 66Fairbanks North Star Borough, AK — combined 41/100, moisture 50, movement 25, water table 46Haines Borough, AK — combined 43/100, moisture 50, movement 18, water table 66Hoonah-Angoon Census Area, AK — combined 42/100, moisture 49, movement 30, water table 46Juneau City and Borough, AK — combined 43/100, moisture 50, movement 30, water table 46Kenai Peninsula Borough, AK — combined 38/100, moisture 50, movement 16, water table 46Ketchikan Gateway Borough, AK — combined 50/100, moisture 49, movement 28, water table 82Kodiak Island Borough, AK — combined 48/100, moisture 51, movement 20, water table 82Lake and Peninsula Borough, AK — combined 44/100, moisture 50, movement 34, water table 46Matanuska-Susitna Borough, AK — combined 47/100, moisture 48, movement 32, water table 66Nome Census Area, AK — combined 52/100, moisture 48, movement 37, water table 82North Slope Borough, AK — combined 48/100, moisture 49, movement 21, water table 82Northwest Arctic Borough, AK — combined 46/100, moisture 51, movement 14, water table 82Petersburg Borough, AK — combined 45/100, moisture 49, movement 25, water table 66Prince of Wales-Hyder Census Area, AK — combined 43/100, moisture 51, movement 29, water table 46Sitka City and Borough, AK — combined 44/100, moisture 50, movement 20, water table 66Southeast Fairbanks Census Area, AK — combined 43/100, moisture 51, movement 16, water table 66Wrangell City and Borough, AK — combined 45/100, moisture 50, movement 38, water table 46Yakutat City and Borough, AK — combined 41/100, moisture 51, movement 24, water table 46Yukon-Koyukuk Census Area, AK — combined 38/100, moisture 49, movement 17, water table 46
  • Low (0–27)
  • Moderate (28–49)
  • Elevated (50–74)
  • High (75–100)

County boundaries: US Census TIGER (public domain), simplified for display. Colours are our index from USDA SSURGO fields where loaded, otherwise from our regional model — each county page states which. How the index is calculated.

CountyIndexMoistureCracksWater tableRegion
Nome Census Area52483782Alaska: permafrost and frost-susceptible ground
Skagway Municipality51483482Alaska: permafrost and frost-susceptible ground
Ketchikan Gateway Borough50492882Alaska: permafrost and frost-susceptible ground
Kusilvak Census Area50473082Alaska: permafrost and frost-susceptible ground
Aleutians West Census Area48503166Alaska: permafrost and frost-susceptible ground
Kodiak Island Borough48512082Alaska: permafrost and frost-susceptible ground
North Slope Borough48492182Alaska: permafrost and frost-susceptible ground
Matanuska-Susitna Borough47483266Alaska: permafrost and frost-susceptible ground
Aleutians East Borough46472966Alaska: permafrost and frost-susceptible ground
Dillingham Census Area46512466Alaska: permafrost and frost-susceptible ground
Northwest Arctic Borough46511482Alaska: permafrost and frost-susceptible ground
Petersburg Borough45492566Alaska: permafrost and frost-susceptible ground
Wrangell City and Borough45503846Alaska: permafrost and frost-susceptible ground
Lake and Peninsula Borough44503446Alaska: permafrost and frost-susceptible ground
Sitka City and Borough44502066Alaska: permafrost and frost-susceptible ground
Anchorage Municipality43483446Alaska: permafrost and frost-susceptible ground
Haines Borough43501866Alaska: permafrost and frost-susceptible ground
Juneau City and Borough43503046Alaska: permafrost and frost-susceptible ground
Prince of Wales-Hyder Census Area43512946Alaska: permafrost and frost-susceptible ground
Southeast Fairbanks Census Area43511666Alaska: permafrost and frost-susceptible ground
Copper River Census Area42493046Alaska: permafrost and frost-susceptible ground
Denali Borough42512846Alaska: permafrost and frost-susceptible ground
Hoonah-Angoon Census Area42493046Alaska: permafrost and frost-susceptible ground
Bethel Census Area41512446Alaska: permafrost and frost-susceptible ground
Fairbanks North Star Borough41502546Alaska: permafrost and frost-susceptible ground
Yakutat City and Borough41512446Alaska: permafrost and frost-susceptible ground
Bristol Bay Borough39492046Alaska: permafrost and frost-susceptible ground
Kenai Peninsula Borough38501646Alaska: permafrost and frost-susceptible ground
Yukon-Koyukuk Census Area38491746Alaska: 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