Photo credit: Woods Hole Research Center
Alaska's Permafrost Is Thawing. (The New York Times, 8/23/2017)
The main road in Bethel, where average temperatures have risen about 4 degrees Fahrenheit since the mid-20th century, is more of a washboard than a thoroughfare because of shifting ground. Building foundations in Bethel move and crack as well. Some roads, airport runways and parking areas have to be reinforced with liquid-filled pipes that transfer heat out of the permafrost to keep the ground from slumping.
The thawing of permafrost is a gradual process. Ground is fully frozen in winter, and begins to thaw from the top down as air temperatures rise in spring. As average temperatures increase over years, this thawed, or active, layer can increase in depth.
Other climate change as a matter of fact posts:
New Orleans. (8/12/2017)
The Netherlands. (6/19/2017)
Global Seed Vault on the Norwegian island of Spitsbergen. (5/20/2017)
Madeline Island, Wisconsin. (2/23/2017)
Mexico City. (2/19/2017)
Moose of Maine. (1/21/2017)
Florida Keys. (1/14/2017)
California wine country. (1/11/2017)
Kaktovik, Alaska. (12/20/2016)
Alaska's Glacier Bay National Park. (7/7/2016)