WORKING GROUP 6 
LEIGHTY 
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tion from airphotos one must first determine the evolution of the landscape, 
trace the events responsible, and relate the two. When this is done, the process 
of evaluation becomes an expected reality - not a chance occurrence. 
Arctic Terrain and Permafrost 
Nearly all of the more common landforms occur in the Arctic areas that are 
found in the more temperate climates. Thus, the configuration aspect of the 
terrain resulting from constructional as well as destructional forces is relatively 
unchanged because of the severe environment. Of course, there are landscape 
features common only to such an environment - ice caps, active glaciers and 
the forms resulting from severe frost phenomena. The effect of the severe arctic 
environment on the terrain is expressed in many ways and these are often the 
result of, and reflect the influence of, permafrost and severe frost activity. 
Permanently frozen ground, called “permafrost”, exists where winter freez 
ing exceeds summer thawing. The ground is frozen in depths from a few feet 
to hundreds of feet, except for shallow depths at the surface, termed the 
“active layer”, which is subjected to freeze-thaw cycles. The soil moisture-ice 
conditions in this active zone and disturbance of the thermal regime of the