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Photograph taken 21 March 2010 in Norwich, Vermont. Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary).
Frost heave is the process by which the freezing of water-saturated soil causes the deformation and upward thrust of the ground surface. [3] This process can distort and crack pavement, damage the foundations of buildings and displace soil in regular patterns. Moist, fine-grained soil at certain temperatures is most susceptible to frost heaving.
The basic condition for ice segregation and frost heaving is existence of a region in soil or porous rock which is relatively permeable, is in a temperature range which allows the coexistence of ice and water (in a premelted state), and has a temperature gradient across the region. [7]
These conditions are unusual enough that frost wedging is unlikely to be the dominant process of frost weathering. [11] Frost wedging is most effective where there are daily cycles of melting and freezing of water-saturated rock, so it is unlikely to be significant in the tropics, in polar regions or in arid climates. [5]
Black frost (or "killing frost") is not strictly speaking frost at all, because it is the condition seen in crops when the humidity is too low for frost to form, but the temperature falls so low that plant tissues freeze and die, becoming blackened, hence the term "black frost".
Cryoturbation occurs to varying degrees in most gelisols. The cause of cryoturbation lies in the way in which the repeated freezing of the soil during autumn causes the formation of ice wedges at the most easily erodible parts of the parent rock. If the parent rock is hard, this can cause quite deep erosion of the rock over many years.
Most frost quakes are associated with minor snow cover on the ground without a significant amount of snow to insulate the ground (i.e., less than 6 inches (15 cm)) A rapid temperature drop from approximately freezing to near or below −18 °C (0 °F), which ordinarily occurred on a timescale of 16 to 48 hours.
The ice crystal growth weakens the rocks which, in time, break up. [3] It is caused by the expansion of ice when water freezes, putting considerable stress on the walls of containment. This is actually a very common process in all humid, temperate areas where there is exposed rock, especially porous rocks like sandstone. Sand can often be found ...