University of Alaska Fairbanks    |    Scenarios Network for Alaska + Arctic Planning


Permafrost is defined as that part of the lithosphere in which a naturally occurring temperature below 0°C (32°F) has existed for two or more years. Historically, only the southern coasts were free of permafrost, but ongoing warming is broadening the permafrost-free zone in Alaska..

An area of solid rock or well-drained gravel free of moisture is classified as permafrost if it meets the definition above. However, most permafrost contains ice in quantities ranging from partial filling of the soil pore space to massive formations of segregated ground ice. Once permafrost is established, it stops the infiltration of groundwater and forces melt and rain water to escape by surface drainage.

Choose a location below by community name, coordinates, or by clicking on the map to select a point.

  • ✓  Permafrost extent (Jorgenson et al., 2008)
  • Permafrost extent (Obu et al., 2018)
  • Mean annual ground temperature at active layer, 1986–2005, GIPL model
  • Mean annual ground temperature at active layer, 2036–2065 (NCAR–CCSM4, RCP 8.5), GIPL model
  • Mean annual ground temperature at top of permafrost, 2000–2016 (modeled)
  • Ground ice volume (Jorgenson et al., 2008)