Frostline.info

Frost line depth in Alaska

Estimated frost depth in typical soil runs from 23″ to 89″ across Alaska's 33 counties. Pick your county or enter a ZIP code for a local estimate.

Deepest frost

  1. North Slope Borough 89″
  2. Northwest Arctic Borough 84″
  3. Southeast Fairbanks Census Area 82″
  4. Fairbanks North Star Borough 81″
  5. Yukon-Koyukuk Census Area 80″

Mildest

  1. Prince of Wales-Outer Ketchikan Borough 23″
  2. Ketchikan Gateway Borough 23″
  3. Prince of Wales-Hyder Census Area 28″
  4. Sitka City and Borough 29″
  5. Wrangell City and Borough 31″

Frost depth by county

CountyEst. frost (typical soil)Typical code range
Aleutians East Borough57″48–72″
Aleutians West Census Area38″30–48″
Anchorage Municipality58″48–72″
Bethel Census Area71″60–84″
Bristol Bay Borough62″48–78″
Chugach Census Area61″48–78″
City and Borough of Juneau44″36–54″
Copper River Census Area80″66–96″
Denali Borough78″60–96″
Dillingham Census Area64″54–78″
Fairbanks North Star Borough81″66–96″
Haines Borough44″36–54″
Hoonah-Angoon Census Area37″30–48″
Juneau City and Borough44″36–54″
Kenai Peninsula Borough55″48–66″
Ketchikan Gateway Borough23″18–30″
Kodiak Island Borough57″48–72″
Kusilvak Census Area73″60–90″
Lake and Peninsula Borough60″48–72″
Matanuska-Susitna Borough61″48–72″
Municipality of Anchorage58″48–72″
Nome Census Area77″60–96″
North Slope Borough89″72–108″
Northwest Arctic Borough84″66–102″
Petersburg Borough37″30–48″
Prince of Wales-Hyder Census Area28″24–36″
Prince of Wales-Outer Ketchikan Borough23″18–30″
Sitka City and Borough29″24–36″
Skagway Municipality44″36–54″
Southeast Fairbanks Census Area82″66–102″
Wrangell City and Borough31″24–42″
Yakutat City and Borough47″42–60″
Yukon-Koyukuk Census Area80″66–96″

Common questions

What is the frost line depth in Alaska?

It ranges from about 23 inches in the mildest county to 89 inches in the coldest, in typical soil.

Which Alaska county has the deepest frost?

North Slope Borough, at about 89 inches in typical soil.