Cracks (or joints) in bedrock allow rain water or snow melt to seep in then
freeze into solid ice, which in turn expands and widens the cracks over time.
Not a one time event, this occurs continuously as the warmth of sunlight thaws
ice then the colder nights freeze the water once again. This freeze/thaw cycle
is common in mid-latitudes. Over time, this process known as frost action (also
called frost wedging) is capable of breaking down and loosening rock material,
inevitably changing the shape and appearance of an entire landscape.
Is this a form of weathering or erosion?
