ABSTRACT
Frost cracking is vertical or sub-vertical fracturing of the ground along a straight line as a result of thermal contraction, or as a curved line by stretching due to dilation cracking over an expanding mound. Thermal contraction cracking occurs in the case of the relatively soft, wet active layer subjected to very cold air temperatures. The cracking on flat areas occurs in a series of relatively straight lines forming a polygonal pattern or tessellon. There are two systems of classification of infilled cracks that are used. In areas with a winter snow pack, the melt-water in the lower part of the isothermal snow in the spring enters any contraction cracks formed during the previous winter and refreezes there, resulting in the formation of ice-wedges. Repeated cracking of the ground at one location can result in two types of wedges.
