Even in the most carefully poured concrete foundation, some minor cracks may be inevitable, especially as the house ages through many freeze/thaw cycles. How might freezing and thawing cause cracks in a foundation? Freezing causes concrete to contract, which can create cracks.
Freezing causes the water in the soil to expand, which can crack the concrete.
Thawing causes the concrete to expand, which can create cracks.
Thawing causes the water in the soil to contract, which can crack the concrete.