Potholes are more prominent during the winter season because of two factors: water and temperature. Potholes form as a result of water accumulation and penetration. When water seeps under the surface, cold temperatures can cause it to freeze and expand. The surrounding area also swells as the water solidifies. Once temperatures go up again, the frozen water will melt, leaving a gap beneath the surface. This significantly weakens the spot where the gap is located. As vehicles drive over the spot, the surface breaks and a pothole remains.