![Yedoma permafrost Exposed permafrost](/subjects/aknatureandscience/images/permafrost_IMG_4914_tile.jpg?maxwidth=650&autorotate=false)
Permafrost Terminology
Permafrostground that remains frozen longer than two consecutive years; ground that doesn't thaw in the summer
Yedoma
an organic-rich Pleistocene-age permafrost with high ice content
Active Layer
in areas with permafrost, the top portion of the soil that thaws and refreezes each year
Ice Wedge
polygon-like pattern on the landscape associated with permafrost caused by repeated cycles of melting, freezing, and cracking
Thermokarst
landscape formations associated with permafrost thaw
Pingo
an earth-covered mound of ice, which creates topography and provides habitat for arctic foxes
Slump
a term that refers to the sagging or degradation of the landscape caused by permafrost thaw
Hydrology
the study of the location, movement, and quality of water on earth; heavily influenced by permafrost in Arctic systems
Erosion
the transport of soil and rock from the earth's surface by wind or water; a significant effect of permafrost thaw
![Aerial view of permafrost polygon patterns in the tundra.](/common/uploads/grid_builder/aknatureandscience/crop16_9/D6647283-A4A9-024E-DB0C53A506A25A70.jpg?width=640&quality=90&mode=crop)
Monitoring Arctic Permafrost
Permafrost underlies most of the Arctic Network and affects nearly everything, from soils and vegetation to water and wildlife.
![A "drunken forest" with trees leaning due to permafrost melt.](/common/uploads/grid_builder/aknatureandscience/crop16_9/D64BC5F9-A03B-A964-83FEBC168F8E6C20.jpg?width=640&quality=90&mode=crop)
Monitoring Central Alaska Permafrost
The Central Alaska Network monitors permafrost to track changes over time, focusing on the thermal and physical state of permafrost.
Learn more about permafrost
Last updated: April 3, 2024