Why are there so many historic stone walls weaving through Connecticut forests? When 18th-century farmers cleared the land, they discovered a never-ending supply of glacial rocks. Even after clearing a field, more rocks would magically appear the next spring. This simulation models frost heaving—the mechanical weathering process where water freezes, expands by 9%, and pushes rocks upward through the soil cycle after cycle.
Amount of water in the soil available to freeze and form ice lenses.
How deep the frost line penetrates the soil during winter.
Unlike almost all other substances, water expands by about 9% when it freezes into ice.
During a New England winter, the freezing front penetrates the soil. Water in the soil freezes, forming ice lenses under rocks. Because water expands, these ice lenses physically lift the rocks upward.
In spring, the ice melts. The cavity left beneath the rock fills with fine soil particles, preventing the rock from falling back down. Over many freeze-thaw cycles, rocks migrate entirely to the surface!