A pothole is a hole or depression in a road surface caused by the combined effects of traffic wear, weather, and pavement deterioration. In Canada, potholes commonly form during freeze-thaw cycles when water seeps into cracks, freezes and expands, then thaws, weakening the pavement until traffic breaks through the surface. Municipal public works departments are responsible for repairing potholes on local roads, while provinces maintain provincial highways. Most municipalities have systems for residents to report potholes, and many prioritize repairs based on severity and traffic volume. Pothole damage to vehicles can sometimes result in municipal liability claims.