The IMD said it has crossed the Mamallapuram coast and weakened after completing its landfall process late Friday. A wall collapsed in T Nagar area of Chennai and caused severe damage to three cars that were parked near it as Mandous raged. Nobody was present inside the vehicles at the time of the incident. Cyclone Mandous: Tamil Nadu Witnesses Heavy Rain, Strong Winds; Wall Collapses As Chennai Reports Waterlogging.