If glaciers had covered the areas, the tors would have been scraped away by the ice. Thus, the tors demonstrate that central Alaska was open to the migration of plants and animals even during the height of the last glaciation. The most accessible tors in Alaska are those seen on the right-hand side of the road as one nears Chena Hot Springs, northeast of Fairbanks. Tors occur on Wickersham Dome where they can be seen from Livengood Road, in inaccessible parts of the Yukon-Tanana Uplands, and on a plateau near the Gerstle River crossed by the Alaska Highway southeast of Big Delta. In Alaska, frost wedging is the main cause.
Water enters fractures in the rocks and freezes.
Repeated freezing and thawing wedges the rock apart. The result is a tor towering over a nearly flat terrace called a cryoplanation terrace.