According to CK-12, ice wedging causes rocks to weather because water expands as it changes from a liquid form to a solid form. Over time, the changes in form wedge the rock apart. For this reason, ice wedging is very effective at weathering rock.
Ice wedging is common in regions where water can go above or below its freezing point, such as in mountain regions like the Sierra Nevada, as stated by CK-12. When water in liquid form freezes to form solid ice, it increases in volume. CK-12 explains that this can be seen when frozen water in an ice cube tray is at a higher level than the liquid water once was, or when a can of soda left in the freezer expands and bends. Ice wedging is a result of water expanding as it goes from liquid form to solid form. Water will work its way into cracks in rocks when the weather is warm. The water in the cracks becomes ice when temperatures drop below freezing. The ice takes up more space and wedges the rock apart over time. At the edge of slopes, large piles of rock broken up by ice wedging can be found as they become loose and tumble down the slopes, according to CK-12.