What must be present on a rock that undergoes frost wed?
In order for a rock to undergo frost wedging, the presence of two main factors is required: water and freezing temperatures.
Water is necessary because frost wedging occurs when water seeps into cracks and pores within a rock. When the temperature drops below freezing, the water freezes and expands, exerting pressure on the surrounding rock.
The freezing temperature is crucial because the expansion of water during freezing is what causes the rock to crack and break apart. If the temperature remains above freezing, the water will not freeze and there will be no expansion or wedging effect on the rock.
Therefore, for frost wedging to occur, a rock must have cracks or pores where water can enter, and the surrounding environment must experience freezing temperatures.