Frost heave occurs when frost penetrates the ground under the foundation footing and water is pulled up from beneath the frozen soil. Once it reaches the freezing zone it solidifies, forming layers of ice – or lenses. These lenses force soil particles to separate and causes the soil surface to heave upwards. Adfreeze is a similar condition where frost heave occurs next to a foundation wall instead of under the foundation footing. When the ice lens melts in the spring, water falls back deep into the soil and a void is created by the melted lens. Adfreeze causes a solar racking foundation to drop to a lower elevation than it was before the frost occurred.