1. Potholes begin after moisture seeps into the native soil below the road surface and subbase gravel. This moisture comes in the form of rain, snow or water seeping into the road bed due to poor road side drainage.
2. As the temperatures drop the ice lenses of frozen water form,causing the ground to expand and push the pavement up as this is the direction of least resistance
3. As the temperatures rise, the ground returns to normal level but the pavement often remains elevated above the once frozen area. This creates a cavity between the pavement and the material below it.
4. When motor vehicles travel over this cavity, the pressure exerted on the unsupported pavement surface cracks after numerous impacts of vehicles traveling over this cavity, finally the pavement crumbles and falls into the cavity leading to a pothole.
