Frost heave
Upward movement of soil caused by ice lenses forming in freezing, moisture-bearing ground. It lifts and cracks slabs and foundations placed above the frost depth.
What does frost heave mean?
Heave requires three ingredients: freezing temperatures, frost-susceptible soil such as silt, and available water. Removing any one of them controls it, which is why drainage and free-draining base material matter as much as footing depth. Damage often appears as a porch, step, or garage slab that rises in winter and settles unevenly in spring.
In practice
A front stoop that lifts every January and sticks against the door is the classic homeowner-visible symptom.