May 2Most potholes are formed due to fatigue of the surface. As fatigue fractures develop they typically interlock in a pattern called alligator cracking. The chunks of pavement between fatigued cracks are worked loose and eventually are thrown out of the surface by continued wheel traffic, thus forming a pothole.
The formation of potholes is increased by low temperatures, as water expands when it freezes to form ice, and puts greater stress on an already cracked pavement or road.

Once a pothole forms, it grows through continued removal of broken chunks of pavement. If a pothole fills with water the growth may be accelerated, as the water will wash loose particles of road surface as vehicles pass. In temperate climates, potholes tend to form most often during spring months when the sub grade is weakend, due to high moisture content.

Potholes can grow to feet in width, though they usually only become a few inches deep, at most. If they become large enough, damage to tires and vehicles can occur. Serious accidents can occur as a direct result.